56407721 has 4 divisors (see below), whose sum is σ = 57932292. Its totient is φ = 54883152.

The previous prime is 56407709. The next prime is 56407739. The reversal of 56407721 is 12770465.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 12770465 = 5 ⋅2554093.

It can be written as a sum of positive squares in 2 ways, for example, as 27678121 + 28729600 = 5261^2 + 5360^2 .

It is a cyclic number.

It is not a de Polignac number, because 56407721 - 2⁶ = 56407657 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (56407781) 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, 762230 + ... + 762303.

It is an arithmetic number, because the mean of its divisors is an integer number (14483073).

Almost surely, 2^56407721 is an apocalyptic number.

It is an amenable number.

56407721 is a deficient number, since it is larger than the sum of its proper divisors (1524571).

56407721 is a wasteful number, since it uses less digits than its factorization.

56407721 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1524570.

The product of its (nonzero) digits is 11760, while the sum is 32.

The square root of 56407721 is about 7510.5073730075. The cubic root of 56407721 is about 383.5124948687.

The spelling of 56407721 in words is "fifty-six million, four hundred seven thousand, seven hundred twenty-one".