18611987951 has 2 divisors, whose sum is σ = 18611987952. Its totient is φ = 18611987950.

The previous prime is 18611987903. The next prime is 18611987963. The reversal of 18611987951 is 15978911681.

It is a happy number.

It is a strong prime.

It is a cyclic number.

It is not a de Polignac number, because 18611987951 - 2⁶ = 18611987887 is a prime.

It is a Sophie Germain prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (18611987971) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 9305993975 + 9305993976.

It is an arithmetic number, because the mean of its divisors is an integer number (9305993976).

Almost surely, 2^18611987951 is an apocalyptic number.

18611987951 is a deficient number, since it is larger than the sum of its proper divisors (1).

18611987951 is an equidigital number, since it uses as much as digits as its factorization.

18611987951 is an evil number, because the sum of its binary digits is even.

The product of its digits is 1088640, while the sum is 56.

The spelling of 18611987951 in words is "eighteen billion, six hundred eleven million, nine hundred eighty-seven thousand, nine hundred fifty-one".