651599991 has 48 divisors (see below), whose sum is σ = 1139854080. Its totient is φ = 366735600.

The previous prime is 651599983. The next prime is 651600011. The reversal of 651599991 is 199995156.

It is not a de Polignac number, because 651599991 - 2³ = 651599983 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (651599951) by changing a digit.

It is a polite number, since it can be written in 47 ways as a sum of consecutive naturals, for example, 84966 + ... + 92316.

It is an arithmetic number, because the mean of its divisors is an integer number (23746960).

Almost surely, 2^651599991 is an apocalyptic number.

651599991 is a deficient number, since it is larger than the sum of its proper divisors (488254089).

651599991 is a wasteful number, since it uses less digits than its factorization.

651599991 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 7441 (or 7428 counting only the distinct ones).

The product of its digits is 984150, while the sum is 54.

The square root of 651599991 is about 25526.4566871315. The cubic root of 651599991 is about 866.9492792493.

The spelling of 651599991 in words is "six hundred fifty-one million, five hundred ninety-nine thousand, nine hundred ninety-one".