621621221 has 8 divisors (see below), whose sum is σ = 670808544. Its totient is φ = 572629680.

The previous prime is 621621199. The next prime is 621621257. The reversal of 621621221 is 122126126.

It is a happy number.

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

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-621621221 is a prime.

It is a Duffinian number.

It is a Curzon number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (621621281) 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, 42311 + ... + 55076.

It is an arithmetic number, because the mean of its divisors is an integer number (83851068).

Almost surely, 2^621621221 is an apocalyptic number.

It is an amenable number.

621621221 is a deficient number, since it is larger than the sum of its proper divisors (49187323).

621621221 is a wasteful number, since it uses less digits than its factorization.

621621221 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 97891.

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

The square root of 621621221 is about 24932.3328431176. The cubic root of 621621221 is about 853.4444870500. Note that the first 4 decimals are identical.

Adding to 621621221 its reverse (122126126), we get a palindrome (743747347).

The spelling of 621621221 in words is "six hundred twenty-one million, six hundred twenty-one thousand, two hundred twenty-one".