55697581 has 2 divisors, whose sum is σ = 55697582. Its totient is φ = 55697580.

The previous prime is 55697549. The next prime is 55697657. The reversal of 55697581 is 18579655.

55697581 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 47141956 + 8555625 = 6866^2 + 2925^2 .

It is a cyclic number.

It is not a de Polignac number, because 55697581 - 2⁵ = 55697549 is a prime.

It is a super-2 number, since 2×55697581² = 6204441058503122, which contains 22 as substring.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (55697281) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 27848790 + 27848791.

It is an arithmetic number, because the mean of its divisors is an integer number (27848791).

Almost surely, 2^55697581 is an apocalyptic number.

It is an amenable number.

55697581 is a deficient number, since it is larger than the sum of its proper divisors (1).

55697581 is an equidigital number, since it uses as much as digits as its factorization.

55697581 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 378000, while the sum is 46.

The square root of 55697581 is about 7463.0812001478. The cubic root of 55697581 is about 381.8962945919.

The spelling of 55697581 in words is "fifty-five million, six hundred ninety-seven thousand, five hundred eighty-one".