621381408 has 24 divisors (see below), whose sum is σ = 1631126448. Its totient is φ = 207127104.

The previous prime is 621381403. The next prime is 621381419. The reversal of 621381408 is 804183126.

It is a tau number, because it is divible by the number of its divisors (24).

It is a super-2 number, since 2×621381408² = 772229708416124928, which contains 22 as substring.

It is not an unprimeable number, because it can be changed into a prime (621381403) 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, 3236266 + ... + 3236457.

It is an arithmetic number, because the mean of its divisors is an integer number (67963602).

Almost surely, 2^621381408 is an apocalyptic number.

It is an amenable number.

621381408 is an abundant number, since it is smaller than the sum of its proper divisors (1009745040).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

621381408 is a wasteful number, since it uses less digits than its factorization.

621381408 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 6472736 (or 6472728 counting only the distinct ones).

The product of its (nonzero) digits is 9216, while the sum is 33.

The square root of 621381408 is about 24927.5231019851. The cubic root of 621381408 is about 853.3347238476.

It can be divided in two parts, 62138 and 1408, that added together give a triangular number (63546 = T₃₅₆).

The spelling of 621381408 in words is "six hundred twenty-one million, three hundred eighty-one thousand, four hundred eight".