421387521 has 4 divisors (see below), whose sum is σ = 561850032. Its totient is φ = 280925012.

The previous prime is 421387513. The next prime is 421387541. The reversal of 421387521 is 125783124.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4.

It is a cyclic number.

It is not a de Polignac number, because 421387521 - 2³ = 421387513 is a prime.

It is not an unprimeable number, because it can be changed into a prime (421387511) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 70231251 + ... + 70231256.

It is an arithmetic number, because the mean of its divisors is an integer number (140462508).

Almost surely, 2^421387521 is an apocalyptic number.

It is an amenable number.

421387521 is a deficient number, since it is larger than the sum of its proper divisors (140462511).

421387521 is a wasteful number, since it uses less digits than its factorization.

421387521 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 140462510.

The product of its digits is 13440, while the sum is 33.

The square root of 421387521 is about 20527.7256655480. The cubic root of 421387521 is about 749.7110122179.

The spelling of 421387521 in words is "four hundred twenty-one million, three hundred eighty-seven thousand, five hundred twenty-one".