394397816121 has 15 divisors (see below), whose sum is σ = 589170613141. Its totient is φ = 262928109348.

The previous prime is 394397816077. The next prime is 394397816341. The reversal of 394397816121 is 121618793493.

The square root of 394397816121 is 628011.

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

394397816121 is a `hidden beast` number, since 3 + 9 + 439 + 7 + 81 + 6 + 121 = 666.

It is a de Polignac number, because none of the positive numbers 2^k-394397816121 is a prime.

It is a super-2 number, since 2×394397816121² (a number of 24 digits) contains 22 as substring.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (394397816821) by changing a digit.

It is a polite number, since it can be written in 14 ways as a sum of consecutive naturals, for example, 5617210 + ... + 5686988.

Almost surely, 2^394397816121 is an apocalyptic number.

394397816121 is the 628011-st square number.

394397816121 is the 314006-th centered octagonal number.

It is an amenable number.

394397816121 is a deficient number, since it is larger than the sum of its proper divisors (194772797020).

394397816121 is an frugal number, since it uses more digits than its factorization.

394397816121 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 139570 (or 69782 counting only the distinct ones).

The product of its digits is 1959552, while the sum is 54.

The spelling of 394397816121 in words is "three hundred ninety-four billion, three hundred ninety-seven million, eight hundred sixteen thousand, one hundred twenty-one".