399726153121 has 9 divisors (see below), whose sum is σ = 402388318899. Its totient is φ = 397081497384.

The previous prime is 399726153097. The next prime is 399726153133. The reversal of 399726153121 is 121351627993.

It is a happy number.

The square root of 399726153121 is 632239.

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

It can be written as a sum of positive squares in only one way, i.e., 117165867025 + 282560286096 = 342295^2 + 531564^2 .

It is not a de Polignac number, because 399726153121 - 2¹⁹ = 399725628833 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (399726153181) 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, 99259510 + ... + 99263536.

It is an arithmetic number, because the mean of its divisors is an integer number (44709813211).

Almost surely, 2^399726153121 is an apocalyptic number.

399726153121 is the 632239-th square number.

399726153121 is the 316120-th centered octagonal number.

It is an amenable number.

399726153121 is a deficient number, since it is larger than the sum of its proper divisors (2662165778).

399726153121 is an frugal number, since it uses more digits than its factorization.

399726153121 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 8368 (or 4184 counting only the distinct ones).

The product of its digits is 612360, while the sum is 49.

Multiplying 399726153121 by its sum of digits (49), we get a square (19586581502929 = 4425673²).

The spelling of 399726153121 in words is "three hundred ninety-nine billion, seven hundred twenty-six million, one hundred fifty-three thousand, one hundred twenty-one".