421520540 has 72 divisors (see below), whose sum is σ = 1074542112. Its totient is φ = 138230400.

The previous prime is 421520531. The next prime is 421520557. The reversal of 421520540 is 45025124.

It is a happy number.

It is a Harshad number since it is a multiple of its sum of digits (23).

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 13190 + ... + 31890.

It is an arithmetic number, because the mean of its divisors is an integer number (14924196).

Almost surely, 2^421520540 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 421520540, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (537271056).

421520540 is an abundant number, since it is smaller than the sum of its proper divisors (653021572).

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

421520540 is a wasteful number, since it uses less digits than its factorization.

421520540 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 18747 (or 18738 counting only the distinct ones).

The product of its (nonzero) digits is 1600, while the sum is 23.

The square root of 421520540 is about 20530.9653937656. The cubic root of 421520540 is about 749.7898907739.

Adding to 421520540 its reverse (45025124), we get a palindrome (466545664).

The spelling of 421520540 in words is "four hundred twenty-one million, five hundred twenty thousand, five hundred forty".