621621401 has 4 divisors (see below), whose sum is σ = 630376704. Its totient is φ = 612866100.

The previous prime is 621621379. The next prime is 621621419. The reversal of 621621401 is 104126126.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-621621401 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (621621431) 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, 4377545 + ... + 4377686.

It is an arithmetic number, because the mean of its divisors is an integer number (157594176).

Almost surely, 2^621621401 is an apocalyptic number.

It is an amenable number.

621621401 is a deficient number, since it is larger than the sum of its proper divisors (8755303).

621621401 is an equidigital number, since it uses as much as digits as its factorization.

621621401 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 8755302.

The product of its (nonzero) digits is 576, while the sum is 23.

The square root of 621621401 is about 24932.3364528878. The cubic root of 621621401 is about 853.4445694259. Note that the first 3 decimals are identical.

Adding to 621621401 its reverse (104126126), we get a palindrome (725747527).

The spelling of 621621401 in words is "six hundred twenty-one million, six hundred twenty-one thousand, four hundred one".