64988981 has 2 divisors, whose sum is σ = 64988982. Its totient is φ = 64988980.

The previous prime is 64988951. The next prime is 64988999. The reversal of 64988981 is 18988946.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 63123025 + 1865956 = 7945^2 + 1366^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-64988981 is a prime.

It is a super-2 number, since 2×64988981² = 8447135302836722, which contains 22 as substring.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (64988951) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 32494490 + 32494491.

It is an arithmetic number, because the mean of its divisors is an integer number (32494491).

Almost surely, 2^64988981 is an apocalyptic number.

It is an amenable number.

64988981 is a deficient number, since it is larger than the sum of its proper divisors (1).

64988981 is an equidigital number, since it uses as much as digits as its factorization.

64988981 is an evil number, because the sum of its binary digits is even.

The product of its digits is 995328, while the sum is 53.

The square root of 64988981 is about 8061.5743499642. The cubic root of 64988981 is about 402.0498543815.

The spelling of 64988981 in words is "sixty-four million, nine hundred eighty-eight thousand, nine hundred eighty-one".