16400131969 has 9 divisors (see below), whose sum is σ = 17760525699. Its totient is φ = 15137046600.

The previous prime is 16400131967. The next prime is 16400131973. The reversal of 16400131969 is 96913100461.

It is a happy number.

The square root of 16400131969 is 128063.

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., 2426055025 + 13974076944 = 49255^2 + 118212^2 .

It is not a de Polignac number, because 16400131969 - 2¹ = 16400131967 is a prime.

It is a super-2 number, since 2×16400131969² (a number of 21 digits) contains 22 as substring.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (16400131967) 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, 1659894 + ... + 1669744.

Almost surely, 2^16400131969 is an apocalyptic number.

16400131969 is the 128063-rd square number.

16400131969 is the 64032-nd centered octagonal number.

It is an amenable number.

16400131969 is a deficient number, since it is larger than the sum of its proper divisors (1360393730).

16400131969 is an frugal number, since it uses more digits than its factorization.

16400131969 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 19728 (or 9864 counting only the distinct ones).

The product of its (nonzero) digits is 34992, while the sum is 40.

The spelling of 16400131969 in words is "sixteen billion, four hundred million, one hundred thirty-one thousand, nine hundred sixty-nine".