651381561 has 8 divisors (see below), whose sum is σ = 965009760. Its totient is φ = 434254356.

The previous prime is 651381553. The next prime is 651381583. The reversal of 651381561 is 165183156.

651381561 is a `hidden beast` number, since 6 + 5 + 13 + 81 + 561 = 666.

It is not a de Polignac number, because 651381561 - 2³ = 651381553 is a prime.

It is not an unprimeable number, because it can be changed into a prime (651381361) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 12062595 + ... + 12062648.

It is an arithmetic number, because the mean of its divisors is an integer number (120626220).

Almost surely, 2^651381561 is an apocalyptic number.

It is an amenable number.

651381561 is a deficient number, since it is larger than the sum of its proper divisors (313628199).

651381561 is a wasteful number, since it uses less digits than its factorization.

651381561 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 24125252 (or 24125246 counting only the distinct ones).

The product of its digits is 21600, while the sum is 36.

The square root of 651381561 is about 25522.1778263533. The cubic root of 651381561 is about 866.8523952214.

The spelling of 651381561 in words is "six hundred fifty-one million, three hundred eighty-one thousand, five hundred sixty-one".