64966981 has 4 divisors (see below), whose sum is σ = 64989964. Its totient is φ = 64944000.

The previous prime is 64966969. The next prime is 64966991. The reversal of 64966981 is 18966946.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 18966946 = 2 ⋅9483473.

It can be written as a sum of positive squares in 2 ways, for example, as 43428100 + 21538881 = 6590^2 + 4641^2 .

It is a cyclic number.

It is not a de Polignac number, because 64966981 - 2⁵ = 64966949 is a prime.

It is a super-2 number, since 2×64966981² = 8441417240508722, which contains 22 as substring.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (64966921) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 6540 + ... + 13141.

It is an arithmetic number, because the mean of its divisors is an integer number (16247491).

Almost surely, 2^64966981 is an apocalyptic number.

It is an amenable number.

64966981 is a deficient number, since it is larger than the sum of its proper divisors (22983).

64966981 is a wasteful number, since it uses less digits than its factorization.

64966981 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 22982.

The product of its digits is 559872, while the sum is 49.

The square root of 64966981 is about 8060.2097367252. The cubic root of 64966981 is about 402.0044820998.

The spelling of 64966981 in words is "sixty-four million, nine hundred sixty-six thousand, nine hundred eighty-one".