621671391 has 24 divisors (see below), whose sum is σ = 988775424. Its totient is φ = 373242960.

The previous prime is 621671387. The next prime is 621671399. The reversal of 621671391 is 193176126.

It is not a de Polignac number, because 621671391 - 2² = 621671387 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (621671399) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 18751 + ... + 39936.

It is an arithmetic number, because the mean of its divisors is an integer number (41198976).

Almost surely, 2^621671391 is an apocalyptic number.

621671391 is a deficient number, since it is larger than the sum of its proper divisors (367104033).

621671391 is a wasteful number, since it uses less digits than its factorization.

621671391 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 58811 (or 58808 counting only the distinct ones).

The product of its digits is 13608, while the sum is 36.

The square root of 621671391 is about 24933.3389460778. The cubic root of 621671391 is about 853.4674464539.

The spelling of 621671391 in words is "six hundred twenty-one million, six hundred seventy-one thousand, three hundred ninety-one".