16431989142321 has 9 divisors (see below), whose sum is σ = 23735112993579. Its totient is φ = 10954651320936.

The previous prime is 16431989142313. The next prime is 16431989142329. The reversal of 16431989142321 is 12324198913461.

The square root of 16431989142321 is 4053639.

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

16431989142321 is a `hidden beast` number, since 1 + 6 + 4 + 3 + 198 + 9 + 1 + 423 + 21 = 666.

It is an interprime number because it is at equal distance from previous prime (16431989142313) and next prime (16431989142329).

It can be written as a sum of positive squares in only one way, i.e., 13813301390625 + 2618687751696 = 3716625^2 + 1618236^2 .

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

It is not a de Polignac number, because 16431989142321 - 2³ = 16431989142313 is a prime.

It is not an unprimeable number, because it can be changed into a prime (16431989142329) 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, 11485311 + ... + 12836523.

Almost surely, 2^{16431989142321} is an apocalyptic number.

16431989142321 is the 4053639-th square number.

16431989142321 is the 2026820-th centered octagonal number.

It is an amenable number.

16431989142321 is a deficient number, since it is larger than the sum of its proper divisors (7303123851258).

16431989142321 is an frugal number, since it uses more digits than its factorization.

16431989142321 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2702432 (or 1351216 counting only the distinct ones).

The product of its digits is 2239488, while the sum is 54.

The spelling of 16431989142321 in words is "sixteen trillion, four hundred thirty-one billion, nine hundred eighty-nine million, one hundred forty-two thousand, three hundred twenty-one".