651085891 has 4 divisors (see below), whose sum is σ = 651682672. Its totient is φ = 650489112.

The previous prime is 651085871. The next prime is 651085921. The reversal of 651085891 is 198580156.

It is a semiprime because it is the product of two primes.

It is a cyclic number.

It is not a de Polignac number, because 651085891 - 2¹⁷ = 650954819 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (651085811) 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, 296751 + ... + 298936.

It is an arithmetic number, because the mean of its divisors is an integer number (162920668).

Almost surely, 2^651085891 is an apocalyptic number.

651085891 is a deficient number, since it is larger than the sum of its proper divisors (596781).

651085891 is a wasteful number, since it uses less digits than its factorization.

651085891 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 596780.

The product of its (nonzero) digits is 86400, while the sum is 43.

The square root of 651085891 is about 25516.3847556820. The cubic root of 651085891 is about 866.7212170956.

The spelling of 651085891 in words is "six hundred fifty-one million, eighty-five thousand, eight hundred ninety-one".