621855881 has 4 divisors (see below), whose sum is σ = 626752512. Its totient is φ = 616959252.

The previous prime is 621855863. The next prime is 621855907. The reversal of 621855881 is 188558126.

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, and also an emirpimes, since its reverse is a distinct semiprime: 188558126 = 2 ⋅94279063.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-621855881 is a prime.

It is a super-2 number, since 2×621855881² = 773409473468572322, which contains 22 as substring.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (621855181) 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, 2448125 + ... + 2448378.

It is an arithmetic number, because the mean of its divisors is an integer number (156688128).

Almost surely, 2^621855881 is an apocalyptic number.

It is an amenable number.

621855881 is a deficient number, since it is larger than the sum of its proper divisors (4896631).

621855881 is a wasteful number, since it uses less digits than its factorization.

621855881 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 4896630.

The product of its digits is 153600, while the sum is 44.

The square root of 621855881 is about 24937.0383365788. The cubic root of 621855881 is about 853.5518643839.

The spelling of 621855881 in words is "six hundred twenty-one million, eight hundred fifty-five thousand, eight hundred eighty-one".