56628021 has 4 divisors (see below), whose sum is σ = 75504032. Its totient is φ = 37752012.

The previous prime is 56627959. The next prime is 56628031. The reversal of 56628021 is 12082665.

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 not a de Polignac number, because 56628021 - 2⁶ = 56627957 is a prime.

It is a super-3 number, since 3×56628021³ (a number of 24 digits) contains 333 as substring.

It is a Duffinian number.

It is a self number, because there is not a number n which added to its sum of digits gives 56628021.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (56628031) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 9438001 + ... + 9438006.

It is an arithmetic number, because the mean of its divisors is an integer number (18876008).

Almost surely, 2^56628021 is an apocalyptic number.

It is an amenable number.

56628021 is a deficient number, since it is larger than the sum of its proper divisors (18876011).

56628021 is a wasteful number, since it uses less digits than its factorization.

56628021 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 18876010.

The product of its (nonzero) digits is 5760, while the sum is 30.

The square root of 56628021 is about 7525.1592009738. The cubic root of 56628021 is about 384.0111148584.

The spelling of 56628021 in words is "fifty-six million, six hundred twenty-eight thousand, twenty-one".