621660121 has 8 divisors (see below), whose sum is σ = 627697224. Its totient is φ = 615632640.

The previous prime is 621660113. The next prime is 621660187. The reversal of 621660121 is 121066126.

It can be written as a sum of positive squares in 4 ways, for example, as 15515721 + 606144400 = 3939^2 + 24620^2 .

It is a sphenic number, since it is the product of 3 distinct primes.

It is a cyclic number.

It is not a de Polignac number, because 621660121 - 2³ = 621660113 is a prime.

It is a super-2 number, since 2×621660121² = 772922612083469282, which contains 22 as substring.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (621660191) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 249735 + ... + 252211.

It is an arithmetic number, because the mean of its divisors is an integer number (78462153).

Almost surely, 2^621660121 is an apocalyptic number.

It is an amenable number.

621660121 is a deficient number, since it is larger than the sum of its proper divisors (6037103).

621660121 is a wasteful number, since it uses less digits than its factorization.

621660121 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 4811.

The product of its (nonzero) digits is 864, while the sum is 25.

The square root of 621660121 is about 24933.1129424306. The cubic root of 621660121 is about 853.4622890473.

The spelling of 621660121 in words is "six hundred twenty-one million, six hundred sixty thousand, one hundred twenty-one".