55551681 has 6 divisors (see below), whose sum is σ = 80241330. Its totient is φ = 37034448.

The previous prime is 55551673. The next prime is 55551701. The reversal of 55551681 is 18615555.

It can be written as a sum of positive squares in only one way, i.e., 43441281 + 12110400 = 6591^2 + 3480^2 .

It is not a de Polignac number, because 55551681 - 2³ = 55551673 is a prime.

It is a super-2 number, since 2×55551681² = 6171978523851522, which contains 22 as substring.

It is not an unprimeable number, because it can be changed into a prime (55552681) by changing a digit.

It is a polite number, since it can be written in 5 ways as a sum of consecutive naturals, for example, 3086196 + ... + 3086213.

It is an arithmetic number, because the mean of its divisors is an integer number (13373555).

Almost surely, 2^55551681 is an apocalyptic number.

It is an amenable number.

55551681 is a deficient number, since it is larger than the sum of its proper divisors (24689649).

55551681 is a wasteful number, since it uses less digits than its factorization.

55551681 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 6172415 (or 6172412 counting only the distinct ones).

The product of its digits is 30000, while the sum is 36.

The square root of 55551681 is about 7453.3000073793. The cubic root of 55551681 is about 381.5625434604.

The spelling of 55551681 in words is "fifty-five million, five hundred fifty-one thousand, six hundred eighty-one".