72521406 has 72 divisors (see below), whose sum is σ = 169008840. Its totient is φ = 23304672.

The previous prime is 72521401. The next prime is 72521411. The reversal of 72521406 is 60412527.

72521406 is a `hidden beast` number, since 7 + 252 + 1 + 406 = 666.

It is an interprime number because it is at equal distance from previous prime (72521401) and next prime (72521411).

It is a Harshad number since it is a multiple of its sum of digits (27).

It is a Curzon number.

It is a self number, because there is not a number n which added to its sum of digits gives 72521406.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (72521401) by changing a digit.

It is a polite number, since it can be written in 35 ways as a sum of consecutive naturals, for example, 665280 + ... + 665388.

It is an arithmetic number, because the mean of its divisors is an integer number (2347345).

Almost surely, 2^72521406 is an apocalyptic number.

It is a practical number, because each smaller number is the sum of distinct divisors of 72521406, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (84504420).

72521406 is an abundant number, since it is smaller than the sum of its proper divisors (96487434).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

72521406 is a wasteful number, since it uses less digits than its factorization.

72521406 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 200 (or 151 counting only the distinct ones).

The product of its (nonzero) digits is 3360, while the sum is 27.

The square root of 72521406 is about 8515.9500937946. The cubic root of 72521406 is about 417.0185799909.

It can be divided in two parts, 72521 and 406, that added together give a palindrome (72927).

The spelling of 72521406 in words is "seventy-two million, five hundred twenty-one thousand, four hundred six".