651599961 has 4 divisors (see below), whose sum is σ = 868799952. Its totient is φ = 434399972.

The previous prime is 651599951. The next prime is 651599969. The reversal of 651599961 is 169995156.

It is a happy number.

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.

It is a cyclic number.

It is not a de Polignac number, because 651599961 - 2⁷ = 651599833 is a prime.

It is not an unprimeable number, because it can be changed into a prime (651599969) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 108599991 + ... + 108599996.

It is an arithmetic number, because the mean of its divisors is an integer number (217199988).

Almost surely, 2^651599961 is an apocalyptic number.

It is an amenable number.

651599961 is a deficient number, since it is larger than the sum of its proper divisors (217199991).

651599961 is a wasteful number, since it uses less digits than its factorization.

651599961 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 217199990.

The product of its digits is 656100, while the sum is 51.

The square root of 651599961 is about 25526.4560995059. The cubic root of 651599961 is about 866.9492659443.

The spelling of 651599961 in words is "six hundred fifty-one million, five hundred ninety-nine thousand, nine hundred sixty-one".