651312981 has 80 divisors (see below), whose sum is σ = 1101754368. Its totient is φ = 380052000.

The previous prime is 651312979. The next prime is 651312983. The reversal of 651312981 is 189213156.

It is an interprime number because it is at equal distance from previous prime (651312979) and next prime (651312983).

It is not a de Polignac number, because 651312981 - 2¹ = 651312979 is a prime.

It is a super-2 number, since 2×651312981² = 848417198438212722, which contains 22 as substring.

It is a Smith number, since the sum of its digits (36) coincides with the sum of the digits of its prime factors.

Its product of digits (12960) is a multiple of the sum of its prime factors (324).

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (651312983) 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 79 ways as a sum of consecutive naturals, for example, 4313256 + ... + 4313406.

Almost surely, 2^651312981 is an apocalyptic number.

It is an amenable number.

651312981 is a deficient number, since it is larger than the sum of its proper divisors (450441387).

651312981 is a wasteful number, since it uses less digits than its factorization.

651312981 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 324 (or 315 counting only the distinct ones).

The product of its digits is 12960, while the sum is 36.

The square root of 651312981 is about 25520.8342536054. The cubic root of 651312981 is about 866.8219722828.

The spelling of 651312981 in words is "six hundred fifty-one million, three hundred twelve thousand, nine hundred eighty-one".