55696721 has 8 divisors (see below), whose sum is σ = 57199464. Its totient is φ = 54213120.

The previous prime is 55696699. The next prime is 55696727. The reversal of 55696721 is 12769655.

It can be written as a sum of positive squares in 4 ways, for example, as 9985600 + 45711121 = 3160^2 + 6761^2 .

It is a sphenic number, since it is the product of 3 distinct primes.

It is a cyclic number.

It is not a de Polignac number, because 55696721 - 2¹⁰ = 55695697 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (55696727) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 1211 + ... + 10623.

It is an arithmetic number, because the mean of its divisors is an integer number (7149933).

Almost surely, 2^55696721 is an apocalyptic number.

It is an amenable number.

55696721 is a deficient number, since it is larger than the sum of its proper divisors (1502743).

55696721 is an equidigital number, since it uses as much as digits as its factorization.

55696721 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 9571.

The product of its digits is 113400, while the sum is 41.

The square root of 55696721 is about 7463.0235829723. The cubic root of 55696721 is about 381.8943290218.

The spelling of 55696721 in words is "fifty-five million, six hundred ninety-six thousand, seven hundred twenty-one".