21275072 has 84 divisors (see below), whose sum is σ = 52431696. Its totient is φ = 8386560.

The previous prime is 21275057. The next prime is 21275077. The reversal of 21275072 is 27057212.

It is a Harshad number since it is a multiple of its sum of digits (26).

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21275077) by changing a digit.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 75572 + ... + 75852.

Almost surely, 2^21275072 is an apocalyptic number.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 21275072, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (26215848).

21275072 is an abundant number, since it is smaller than the sum of its proper divisors (31156624).

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

21275072 is a wasteful number, since it uses less digits than its factorization.

21275072 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 326 (or 303 counting only the distinct ones).

The product of its (nonzero) digits is 1960, while the sum is 26.

The square root of 21275072 is about 4612.4908671996. The cubic root of 21275072 is about 277.0918036016.

The spelling of 21275072 in words is "twenty-one million, two hundred seventy-five thousand, seventy-two".