1626673218921 has 27 divisors (see below), whose sum is σ = 2358944131453. Its totient is φ = 1080171084120.

The previous prime is 1626673218901. The next prime is 1626673218943. The reversal of 1626673218921 is 1298123766261.

It is a happy number.

The square root of 1626673218921 is 1275411.

It is a perfect power (a square), and thus also a powerful number.

1626673218921 is a `hidden beast` number, since 1 + 626 + 6 + 7 + 3 + 2 + 1 + 8 + 9 + 2 + 1 = 666.

It is not a de Polignac number, because 1626673218921 - 2²⁹ = 1626136348009 is a prime.

It is a super-2 number, since 2×1626673218921² (a number of 25 digits) contains 22 as substring.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (1626673218901) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (23) of ones.

It is a polite number, since it can be written in 26 ways as a sum of consecutive naturals, for example, 1189957780 + ... + 1189959146.

Almost surely, 2^{1626673218921} is an apocalyptic number.

1626673218921 is the 1275411-st square number.

1626673218921 is the 637706-th centered octagonal number.

It is an amenable number.

1626673218921 is a deficient number, since it is larger than the sum of its proper divisors (732270912532).

1626673218921 is an frugal number, since it uses more digits than its factorization.

1626673218921 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 3362 (or 1681 counting only the distinct ones).

The product of its digits is 2612736, while the sum is 54.

The spelling of 1626673218921 in words is "one trillion, six hundred twenty-six billion, six hundred seventy-three million, two hundred eighteen thousand, nine hundred twenty-one".