621400643 has 8 divisors (see below), whose sum is σ = 692583120. Its totient is φ = 554065920.

The previous prime is 621400621. The next prime is 621400651. The reversal of 621400643 is 346004126.

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 621400643 - 2¹² = 621396547 is a prime.

It is a super-2 number, since 2×621400643² = 772277518241626898, which contains 22 as substring.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (621400613) 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, 961598 + ... + 962243.

It is an arithmetic number, because the mean of its divisors is an integer number (86572890).

Almost surely, 2^621400643 is an apocalyptic number.

621400643 is a deficient number, since it is larger than the sum of its proper divisors (71182477).

621400643 is a wasteful number, since it uses less digits than its factorization.

621400643 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1923877.

The product of its (nonzero) digits is 3456, while the sum is 26.

The square root of 621400643 is about 24927.9089175165. The cubic root of 621400643 is about 853.3435288122.

Adding to 621400643 its reverse (346004126), we get a palindrome (967404769).

The spelling of 621400643 in words is "six hundred twenty-one million, four hundred thousand, six hundred forty-three".