31816213641 has 15 divisors (see below), whose sum is σ = 47530322301. Its totient is φ = 21209738868.

The previous prime is 31816213631. The next prime is 31816213763. The reversal of 31816213641 is 14631261813.

The square root of 31816213641 is 178371.

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

31816213641 is a `hidden beast` number, since 3 + 1 + 8 + 1 + 6 + 2 + 1 + 3 + 641 = 666.

It is not a de Polignac number, because 31816213641 - 2⁹ = 31816213129 is a prime.

It is a junction number, because it is equal to n+sod(n) for n = 31816213596 and 31816213605.

It is not an unprimeable number, because it can be changed into a prime (31816213631) 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, 1595430 + ... + 1615248.

Almost surely, 2^31816213641 is an apocalyptic number.

31816213641 is the 178371-st square number.

31816213641 is the 89186-th centered octagonal number.

It is an amenable number.

31816213641 is a deficient number, since it is larger than the sum of its proper divisors (15714108660).

31816213641 is an frugal number, since it uses more digits than its factorization.

31816213641 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 39650 (or 19822 counting only the distinct ones).

The product of its digits is 20736, while the sum is 36.

Multiplying 31816213641 by its sum of digits (36), we get a square (1145383691076 = 1070226²).

Multiplying 31816213641 by its product of digits (20736), we get a square (659741006059776 = 25685424²).

The spelling of 31816213641 in words is "thirty-one billion, eight hundred sixteen million, two hundred thirteen thousand, six hundred forty-one".