651294191021 has 4 divisors (see below), whose sum is σ = 651967712352. Its totient is φ = 650620669692.

The previous prime is 651294190979. The next prime is 651294191029. The reversal of 651294191021 is 120191492156.

651294191021 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

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 a de Polignac number, because none of the positive numbers 2^k-651294191021 is a prime.

It is a Duffinian number.

It is a self number, because there is not a number n which added to its sum of digits gives 651294191021.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (651294191029) 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, 336759215 + ... + 336761148.

It is an arithmetic number, because the mean of its divisors is an integer number (162991928088).

Almost surely, 2^651294191021 is an apocalyptic number.

It is an amenable number.

651294191021 is a deficient number, since it is larger than the sum of its proper divisors (673521331).

651294191021 is an equidigital number, since it uses as much as digits as its factorization.

651294191021 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 673521330.

The product of its (nonzero) digits is 38880, while the sum is 41.

The spelling of 651294191021 in words is "six hundred fifty-one billion, two hundred ninety-four million, one hundred ninety-one thousand, twenty-one".