55818981 has 12 divisors (see below), whose sum is σ = 80732652. Its totient is φ = 37164096.

The previous prime is 55818937. The next prime is 55818991. The reversal of 55818981 is 18981855.

55818981 is a `hidden beast` number, since 558 + 1 + 8 + 98 + 1 = 666.

It can be written as a sum of positive squares in 2 ways, for example, as 45360225 + 10458756 = 6735^2 + 3234^2 .

It is not a de Polignac number, because 55818981 - 2¹³ = 55810789 is a prime.

It is a super-2 number, since 2×55818981² = 6231517279756722, which contains 22 as substring.

It is a Smith number, since the sum of its digits (45) coincides with the sum of the digits of its prime factors.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (55818901) by changing a digit.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 4095 + ... + 11331.

It is an arithmetic number, because the mean of its divisors is an integer number (6727721).

Almost surely, 2^55818981 is an apocalyptic number.

It is an amenable number.

55818981 is a deficient number, since it is larger than the sum of its proper divisors (24913671).

55818981 is a wasteful number, since it uses less digits than its factorization.

55818981 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 8100 (or 8097 counting only the distinct ones).

The product of its digits is 115200, while the sum is 45.

The square root of 55818981 is about 7471.2101429420. The cubic root of 55818981 is about 382.1735571824.

The spelling of 55818981 in words is "fifty-five million, eight hundred eighteen thousand, nine hundred eighty-one".