621621917951 has 4 divisors (see below), whose sum is σ = 630377156304. Its totient is φ = 612866679600.

The previous prime is 621621917933. The next prime is 621621917963. The reversal of 621621917951 is 159719126126.

It is a happy number.

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 621621917951 - 2⁶ = 621621917887 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 621621917951.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (621621917351) 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, 4377619070 + ... + 4377619211.

It is an arithmetic number, because the mean of its divisors is an integer number (157594289076).

Almost surely, 2^621621917951 is an apocalyptic number.

621621917951 is a deficient number, since it is larger than the sum of its proper divisors (8755238353).

621621917951 is an equidigital number, since it uses as much as digits as its factorization.

621621917951 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 8755238352.

The product of its digits is 408240, while the sum is 50.

The spelling of 621621917951 in words is "six hundred twenty-one billion, six hundred twenty-one million, nine hundred seventeen thousand, nine hundred fifty-one".