621423540 has 36 divisors (see below), whose sum is σ = 1884985284. Its totient is φ = 165712896.

The previous prime is 621423527. The next prime is 621423563. The reversal of 621423540 is 45324126.

621423540 is a `hidden beast` number, since 621 + 4 + 2 + 35 + 4 + 0 = 666.

It can be written as a sum of positive squares in 2 ways, for example, as 441756324 + 179667216 = 21018^2 + 13404^2 .

It is a tau number, because it is divible by the number of its divisors (36).

It is a super-2 number, since 2×621423540² = 772334432132263200, which contains 22 as substring.

It is a congruent number.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 1725997 + ... + 1726356.

Almost surely, 2^621423540 is an apocalyptic number.

621423540 is a gapful number since it is divisible by the number (60) formed by its first and last digit.

It is an amenable number.

621423540 is an abundant number, since it is smaller than the sum of its proper divisors (1263561744).

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

621423540 is a wasteful number, since it uses less digits than its factorization.

621423540 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 3452368 (or 3452363 counting only the distinct ones).

The product of its (nonzero) digits is 5760, while the sum is 27.

The square root of 621423540 is about 24928.3681776405. The cubic root of 621423540 is about 853.3540098478.

Adding to 621423540 its reverse (45324126), we get a palindrome (666747666).

The spelling of 621423540 in words is "six hundred twenty-one million, four hundred twenty-three thousand, five hundred forty".