81953908452 has 36 divisors (see below), whose sum is σ = 223096752060. Its totient is φ = 25216587072.

The previous prime is 81953908433. The next prime is 81953908483. The reversal of 81953908452 is 25480935918.

It can be written as a sum of positive squares in 2 ways, for example, as 6886676196 + 75067232256 = 82986^2 + 273984^2 .

It is a tau number, because it is divible by the number of its divisors (36).

It is a super-2 number, since 2×81953908452² (a number of 23 digits) contains 22 as substring.

It is an unprimeable number.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 87557127 + ... + 87558062.

Almost surely, 2^81953908452 is an apocalyptic number.

It is an amenable number.

81953908452 is an abundant number, since it is smaller than the sum of its proper divisors (141142843608).

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

81953908452 is a wasteful number, since it uses less digits than its factorization.

81953908452 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 175115212 (or 175115207 counting only the distinct ones).

The product of its (nonzero) digits is 3110400, while the sum is 54.

The spelling of 81953908452 in words is "eighty-one billion, nine hundred fifty-three million, nine hundred eight thousand, four hundred fifty-two".