56406521 has 4 divisors (see below), whose sum is σ = 56449152. Its totient is φ = 56363892.

The previous prime is 56406499. The next prime is 56406547. The reversal of 56406521 is 12560465.

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, and also an emirpimes, since its reverse is a distinct semiprime: 12560465 = 5 ⋅2512093.

It is a cyclic number.

It is not a de Polignac number, because 56406521 - 2⁶ = 56406457 is a prime.

It is a super-2 number, since 2×56406521² = 6363391222646882, which contains 22 as substring.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (56406121) 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, 19265 + ... + 21998.

It is an arithmetic number, because the mean of its divisors is an integer number (14112288).

Almost surely, 2^56406521 is an apocalyptic number.

It is an amenable number.

56406521 is a deficient number, since it is larger than the sum of its proper divisors (42631).

56406521 is a wasteful number, since it uses less digits than its factorization.

56406521 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 42630.

The product of its (nonzero) digits is 7200, while the sum is 29.

The square root of 56406521 is about 7510.4274845045. The cubic root of 56406521 is about 383.5097752750.

Adding to 56406521 its reverse (12560465), we get a palindrome (68966986).

The spelling of 56406521 in words is "fifty-six million, four hundred six thousand, five hundred twenty-one".