621721132 has 12 divisors (see below), whose sum is σ = 1088820936. Its totient is φ = 310629440.

The previous prime is 621721117. The next prime is 621721147. The reversal of 621721132 is 231127126.

It is a happy number.

It is an interprime number because it is at equal distance from previous prime (621721117) and next prime (621721147).

It is a super-2 number, since 2×621721132² = 773074331950722848, which contains 22 as substring.

It is a junction number, because it is equal to n+sod(n) for n = 621721097 and 621721106.

It is an unprimeable number.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 51658 + ... + 62545.

It is an arithmetic number, because the mean of its divisors is an integer number (90735078).

Almost surely, 2^621721132 is an apocalyptic number.

It is an amenable number.

621721132 is a deficient number, since it is larger than the sum of its proper divisors (467099804).

621721132 is a wasteful number, since it uses less digits than its factorization.

621721132 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 115568 (or 115566 counting only the distinct ones).

The product of its digits is 1008, while the sum is 25.

The square root of 621721132 is about 24934.3364058481. The cubic root of 621721132 is about 853.4902083142.

Adding to 621721132 its reverse (231127126), we get a palindrome (852848258).

The spelling of 621721132 in words is "six hundred twenty-one million, seven hundred twenty-one thousand, one hundred thirty-two".