81487211979 has 16 divisors (see below), whose sum is σ = 109854337824. Its totient is φ = 53723712000.

The previous prime is 81487211977. The next prime is 81487211999. The reversal of 81487211979 is 97911278418.

81487211979 = T₂₀₁ + T₂₀₂ + ... + T₇₈₇₇.

It is not a de Polignac number, because 81487211979 - 2¹ = 81487211977 is a prime.

It is a super-2 number, since 2×81487211979² (a number of 23 digits) contains 22 as substring.

It is not an unprimeable number, because it can be changed into a prime (81487211977) 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, 100819 + ... + 416099.

It is an arithmetic number, because the mean of its divisors is an integer number (6865896114).

Almost surely, 2^81487211979 is an apocalyptic number.

81487211979 is a deficient number, since it is larger than the sum of its proper divisors (28367125845).

81487211979 is a wasteful number, since it uses less digits than its factorization.

81487211979 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 316238.

The product of its digits is 2032128, while the sum is 57.

The spelling of 81487211979 in words is "eighty-one billion, four hundred eighty-seven million, two hundred eleven thousand, nine hundred seventy-nine".