56921 has 2 divisors, whose sum is σ = 56922. Its totient is φ = 56920.

The previous prime is 56911. The next prime is 56923. The reversal of 56921 is 12965.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 55696 + 1225 = 236^2 + 35^2 .

It is a cyclic number.

It is not a de Polignac number, because 56921 - 2⁶ = 56857 is a prime.

It is a Sophie Germain prime.

Together with 56923, it forms a pair of twin primes.

It is a Chen prime.

It is an Ulam number.

It is an alternating number because its digits alternate between odd and even.

It is a Curzon number.

It is an inconsummate number, since it does not exist a number n which divided by its sum of digits gives 56921.

It is not a weakly prime, because it can be changed into another prime (56923) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 28460 + 28461.

It is an arithmetic number, because the mean of its divisors is an integer number (28461).

2⁵⁶⁹²¹ is an apocalyptic number.

It is an amenable number.

56921 is a deficient number, since it is larger than the sum of its proper divisors (1).

56921 is an equidigital number, since it uses as much as digits as its factorization.

56921 is an evil number, because the sum of its binary digits is even.

The product of its digits is 540, while the sum is 23.

The square root of 56921 is about 238.5812230667. The cubic root of 56921 is about 38.4672234673.

Subtracting from 56921 its reverse (12965), we obtain a triangular number (43956 = T₂₉₆).

The spelling of 56921 in words is "fifty-six thousand, nine hundred twenty-one".