81887781995 has 16 divisors (see below), whose sum is σ = 99947781120. Its totient is φ = 64398063744.

The previous prime is 81887781991. The next prime is 81887782003. The reversal of 81887781995 is 59918778818.

It is a cyclic number.

It is not a de Polignac number, because 81887781995 - 2² = 81887781991 is a prime.

It is not an unprimeable number, because it can be changed into a prime (81887781991) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 522332 + ... + 660761.

It is an arithmetic number, because the mean of its divisors is an integer number (6246736320).

Almost surely, 2^81887781995 is an apocalyptic number.

81887781995 is a deficient number, since it is larger than the sum of its proper divisors (18059999125).

81887781995 is a wasteful number, since it uses less digits than its factorization.

81887781995 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1183334.

The product of its digits is 81285120, while the sum is 71.

The spelling of 81887781995 in words is "eighty-one billion, eight hundred eighty-seven million, seven hundred eighty-one thousand, nine hundred ninety-five".