16861631 has 2 divisors, whose sum is σ = 16861632. Its totient is φ = 16861630.

The previous prime is 16861609. The next prime is 16861639. The reversal of 16861631 is 13616861.

It is a strong prime.

It is an emirp because it is prime and its reverse (13616861) is a distict prime.

It is a cyclic number.

It is not a de Polignac number, because 16861631 - 2⁶ = 16861567 is a prime.

It is a super-2 number, since 2×16861631² = 568629199960322, which contains 22 as substring.

It is a Chen prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (16861639) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 8430815 + 8430816.

It is an arithmetic number, because the mean of its divisors is an integer number (8430816).

Almost surely, 2^16861631 is an apocalyptic number.

16861631 is a deficient number, since it is larger than the sum of its proper divisors (1).

16861631 is an equidigital number, since it uses as much as digits as its factorization.

16861631 is an evil number, because the sum of its binary digits is even.

The product of its digits is 5184, while the sum is 32.

The square root of 16861631 is about 4106.2916360142. The cubic root of 16861631 is about 256.4286387923.

The spelling of 16861631 in words is "sixteen million, eight hundred sixty-one thousand, six hundred thirty-one".