651085921 has 2 divisors, whose sum is σ = 651085922. Its totient is φ = 651085920.

The previous prime is 651085871. The next prime is 651085927. The reversal of 651085921 is 129580156.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 475894225 + 175191696 = 21815^2 + 13236^2 .

It is a cyclic number.

It is not a de Polignac number, because 651085921 - 2⁷ = 651085793 is a prime.

It is a Chen prime.

It is not a weakly prime, because it can be changed into another prime (651085927) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 325542960 + 325542961.

It is an arithmetic number, because the mean of its divisors is an integer number (325542961).

Almost surely, 2^651085921 is an apocalyptic number.

It is an amenable number.

651085921 is a deficient number, since it is larger than the sum of its proper divisors (1).

651085921 is an equidigital number, since it uses as much as digits as its factorization.

651085921 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 21600, while the sum is 37.

The square root of 651085921 is about 25516.3853435396. The cubic root of 651085921 is about 866.7212304076.

The spelling of 651085921 in words is "six hundred fifty-one million, eighty-five thousand, nine hundred twenty-one".