81456665418 has 64 divisors (see below), whose sum is σ = 191725989120. Its totient is φ = 25546599936.

The previous prime is 81456665393. The next prime is 81456665443.

It is a happy number.

81456665418 is nontrivially palindromic in base 10.

It is an interprime number because it is at equal distance from previous prime (81456665393) and next prime (81456665443).

It is a super-2 number, since 2×81456665418² (a number of 23 digits) contains 22 as substring.

It is a Harshad number since it is a multiple of its sum of digits (54).

It is an unprimeable number.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 3138571 + ... + 3164417.

It is an arithmetic number, because the mean of its divisors is an integer number (2995718580).

Almost surely, 2^81456665418 is an apocalyptic number.

81456665418 is an abundant number, since it is smaller than the sum of its proper divisors (110269323702).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

81456665418 is a wasteful number, since it uses less digits than its factorization.

81456665418 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 29308 (or 29302 counting only the distinct ones).

The product of its digits is 5529600, while the sum is 54.

The spelling of 81456665418 in words is "eighty-one billion, four hundred fifty-six million, six hundred sixty-five thousand, four hundred eighteen".