55664981 has 2 divisors, whose sum is σ = 55664982. Its totient is φ = 55664980.

The previous prime is 55664969. The next prime is 55665013. The reversal of 55664981 is 18946655.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 46362481 + 9302500 = 6809^2 + 3050^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-55664981 is a prime.

It is a super-2 number, since 2×55664981² = 6197180219460722, which contains 22 as substring.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (55664381) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 27832490 + 27832491.

It is an arithmetic number, because the mean of its divisors is an integer number (27832491).

Almost surely, 2^55664981 is an apocalyptic number.

It is an amenable number.

55664981 is a deficient number, since it is larger than the sum of its proper divisors (1).

55664981 is an equidigital number, since it uses as much as digits as its factorization.

55664981 is an evil number, because the sum of its binary digits is even.

The product of its digits is 259200, while the sum is 44.

The square root of 55664981 is about 7460.8967959623. The cubic root of 55664981 is about 381.8217716130.

The spelling of 55664981 in words is "fifty-five million, six hundred sixty-four thousand, nine hundred eighty-one".