1951721213864 has 16 divisors (see below), whose sum is σ = 3659683744800. Its totient is φ = 975805548592.

The previous prime is 1951721213843. The next prime is 1951721213867. The reversal of 1951721213864 is 4683121271591.

It is not an unprimeable number, because it can be changed into a prime (1951721213867) 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, 6731444 + ... + 7015395.

It is an arithmetic number, because the mean of its divisors is an integer number (228730234050).

Almost surely, 2^{1951721213864} is an apocalyptic number.

It is an amenable number.

1951721213864 is a deficient number, since it is larger than the sum of its proper divisors (1707962530936).

1951721213864 is a wasteful number, since it uses less digits than its factorization.

1951721213864 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 13764592 (or 13764588 counting only the distinct ones).

The product of its digits is 725760, while the sum is 50.

The spelling of 1951721213864 in words is "one trillion, nine hundred fifty-one billion, seven hundred twenty-one million, two hundred thirteen thousand, eight hundred sixty-four".