621973453921 has 16 divisors (see below), whose sum is σ = 639027823104. Its totient is φ = 605079947584.

The previous prime is 621973453877. The next prime is 621973453957. The reversal of 621973453921 is 129354379126.

It is a cyclic number.

It is not a de Polignac number, because 621973453921 - 2¹⁷ = 621973322849 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (621973453721) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 57944271 + ... + 57955003.

It is an arithmetic number, because the mean of its divisors is an integer number (39939238944).

Almost surely, 2^621973453921 is an apocalyptic number.

It is an amenable number.

621973453921 is a deficient number, since it is larger than the sum of its proper divisors (17054369183).

621973453921 is a wasteful number, since it uses less digits than its factorization.

621973453921 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 18080.

The product of its digits is 2449440, while the sum is 52.

The spelling of 621973453921 in words is "six hundred twenty-one billion, nine hundred seventy-three million, four hundred fifty-three thousand, nine hundred twenty-one".