56728421 has 2 divisors, whose sum is σ = 56728422. Its totient is φ = 56728420.

The previous prime is 56728417. The next prime is 56728429. The reversal of 56728421 is 12482765.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 48804196 + 7924225 = 6986^2 + 2815^2 .

It is a cyclic number.

It is not a de Polignac number, because 56728421 - 2² = 56728417 is a prime.

It is a super-2 number, since 2×56728421² = 6436227498306482, which contains 22 as substring.

It is a Chen prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (56728429) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 28364210 + 28364211.

It is an arithmetic number, because the mean of its divisors is an integer number (28364211).

Almost surely, 2^56728421 is an apocalyptic number.

It is an amenable number.

56728421 is a deficient number, since it is larger than the sum of its proper divisors (1).

56728421 is an equidigital number, since it uses as much as digits as its factorization.

56728421 is an evil number, because the sum of its binary digits is even.

The product of its digits is 26880, while the sum is 35.

The square root of 56728421 is about 7531.8272019477. The cubic root of 56728421 is about 384.2379280872.

The spelling of 56728421 in words is "fifty-six million, seven hundred twenty-eight thousand, four hundred twenty-one".