64406981 has 2 divisors, whose sum is σ = 64406982. Its totient is φ = 64406980.

The previous prime is 64406971. The next prime is 64406989. The reversal of 64406981 is 18960446.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 32878756 + 31528225 = 5734^2 + 5615^2 .

It is a cyclic number.

It is not a de Polignac number, because 64406981 - 2¹⁸ = 64144837 is a prime.

It is a super-2 number, since 2×64406981² = 8296518403068722, which contains 22 as substring.

It is a Chen prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (64406989) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 32203490 + 32203491.

It is an arithmetic number, because the mean of its divisors is an integer number (32203491).

Almost surely, 2^64406981 is an apocalyptic number.

It is an amenable number.

64406981 is a deficient number, since it is larger than the sum of its proper divisors (1).

64406981 is an equidigital number, since it uses as much as digits as its factorization.

64406981 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 41472, while the sum is 38.

The square root of 64406981 is about 8025.3960026905. The cubic root of 64406981 is about 400.8460861670.

The spelling of 64406981 in words is "sixty-four million, four hundred six thousand, nine hundred eighty-one".