64906981 has 4 divisors (see below), whose sum is σ = 64923264. Its totient is φ = 64890700.

The previous prime is 64906979. The next prime is 64906997. The reversal of 64906981 is 18960946.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4, and also a brilliant number, because the two primes have the same length.

It is a cyclic number.

It is not a de Polignac number, because 64906981 - 2¹ = 64906979 is a prime.

It is a super-2 number, since 2×64906981² = 8425832365068722, 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 (64906931) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 2316 + ... + 11626.

It is an arithmetic number, because the mean of its divisors is an integer number (16230816).

Almost surely, 2^64906981 is an apocalyptic number.

It is an amenable number.

64906981 is a deficient number, since it is larger than the sum of its proper divisors (16283).

64906981 is an equidigital number, since it uses as much as digits as its factorization.

64906981 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 16282.

The product of its (nonzero) digits is 93312, while the sum is 43.

The square root of 64906981 is about 8056.4868894575. The cubic root of 64906981 is about 401.8806874287.

The spelling of 64906981 in words is "sixty-four million, nine hundred six thousand, nine hundred eighty-one".