81630161572 has 24 divisors (see below), whose sum is σ = 143825199840. Its totient is φ = 40538108160.

The previous prime is 81630161549. The next prime is 81630161579. The reversal of 81630161572 is 27516103618.

It is a happy number.

It is a super-2 number, since 2×81630161572² (a number of 23 digits) contains 22 as substring.

It is not an unprimeable number, because it can be changed into a prime (81630161579) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 273172 + ... + 487732.

It is an arithmetic number, because the mean of its divisors is an integer number (5992716660).

Almost surely, 2^81630161572 is an apocalyptic number.

It is an amenable number.

81630161572 is a deficient number, since it is larger than the sum of its proper divisors (62195038268).

81630161572 is a wasteful number, since it uses less digits than its factorization.

81630161572 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 215211 (or 215209 counting only the distinct ones).

The product of its (nonzero) digits is 60480, while the sum is 40.

The spelling of 81630161572 in words is "eighty-one billion, six hundred thirty million, one hundred sixty-one thousand, five hundred seventy-two".