15665561555131 has 2 divisors, whose sum is σ = 15665561555132. Its totient is φ = 15665561555130.

The previous prime is 15665561555027. The next prime is 15665561555173. The reversal of 15665561555131 is 13155516556651.

It is a strong prime.

It is a cyclic number.

It is not a de Polignac number, because 15665561555131 - 2⁹ = 15665561554619 is a prime.

It is a super-2 number, since 2×15665561555131² (a number of 27 digits) contains 22 as substring.

It is not a weakly prime, because it can be changed into another prime (15665561555531) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 7832780777565 + 7832780777566.

It is an arithmetic number, because the mean of its divisors is an integer number (7832780777566).

Almost surely, 2^{15665561555131} is an apocalyptic number.

15665561555131 is a deficient number, since it is larger than the sum of its proper divisors (1).

15665561555131 is an equidigital number, since it uses as much as digits as its factorization.

15665561555131 is an evil number, because the sum of its binary digits is even.

The product of its digits is 10125000, while the sum is 55.

The spelling of 15665561555131 in words is "fifteen trillion, six hundred sixty-five billion, five hundred sixty-one million, five hundred fifty-five thousand, one hundred thirty-one".