621655 has 8 divisors (see below), whose sum is σ = 753984. Its totient is φ = 492000.

The previous prime is 621641. The next prime is 621671. The reversal of 621655 is 556126.

It is a sphenic number, since it is the product of 3 distinct primes.

It is not a de Polignac number, because 621655 - 2⁷ = 621527 is a prime.

It is a Duffinian number.

621655 is a lucky number.

It is a plaindrome in base 9 and base 14.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 111 + ... + 1120.

It is an arithmetic number, because the mean of its divisors is an integer number (94248).

2⁶²¹⁶⁵⁵ is an apocalyptic number.

621655 is a deficient number, since it is larger than the sum of its proper divisors (132329).

621655 is a wasteful number, since it uses less digits than its factorization.

621655 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1337.

The product of its digits is 1800, while the sum is 25.

The square root of 621655 is about 788.4510130630. The cubic root of 621655 is about 85.3459945541.

The spelling of 621655 in words is "six hundred twenty-one thousand, six hundred fifty-five".