8400368958921 has 9 divisors (see below), whose sum is σ = 12133878833479. Its totient is φ = 5600240175936.

The previous prime is 8400368958871. The next prime is 8400368958979. The reversal of 8400368958921 is 1298598630048.

The square root of 8400368958921 is 2898339.

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

8400368958921 is a `hidden beast` number, since 8 + 40 + 0 + 3 + 6 + 8 + 9 + 589 + 2 + 1 = 666.

It can be written as a sum of positive squares in only one way, i.e., 2005863201225 + 6394505757696 = 1416285^2 + 2528736^2 .

It is a tau number, because it is divible by the number of its divisors (9).

It is not a de Polignac number, because 8400368958921 - 2³⁹ = 7850613145033 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (8400368956921) by changing a digit.

It is a polite number, since it can be written in 8 ways as a sum of consecutive naturals, for example, 8211961 + ... + 9178073.

Almost surely, 2^{8400368958921} is an apocalyptic number.

8400368958921 is the 2898339-th square number.

8400368958921 is the 1449170-th centered octagonal number.

It is an amenable number.

8400368958921 is a deficient number, since it is larger than the sum of its proper divisors (3733509874558).

8400368958921 is an frugal number, since it uses more digits than its factorization.

8400368958921 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1932232 (or 966116 counting only the distinct ones).

The product of its (nonzero) digits is 29859840, while the sum is 63.

The spelling of 8400368958921 in words is "eight trillion, four hundred billion, three hundred sixty-eight million, nine hundred fifty-eight thousand, nine hundred twenty-one".