621531901 has 16 divisors (see below), whose sum is σ = 657849600. Its totient is φ = 586575808.

The previous prime is 621531899. The next prime is 621531907. The reversal of 621531901 is 109135126.

It is a cyclic number.

It is not a de Polignac number, because 621531901 - 2¹ = 621531899 is a prime.

It is a self number, because there is not a number n which added to its sum of digits gives 621531901.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (621531907) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 144855 + ... + 149083.

It is an arithmetic number, because the mean of its divisors is an integer number (41115600).

Almost surely, 2^621531901 is an apocalyptic number.

It is an amenable number.

621531901 is a deficient number, since it is larger than the sum of its proper divisors (36317699).

621531901 is a wasteful number, since it uses less digits than its factorization.

621531901 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 4388.

The product of its (nonzero) digits is 1620, while the sum is 28.

The square root of 621531901 is about 24930.5415304201. The cubic root of 621531901 is about 853.4036082906.

The spelling of 621531901 in words is "six hundred twenty-one million, five hundred thirty-one thousand, nine hundred one".