81266551600 has 60 divisors (see below), whose sum is σ = 210261587536. Its totient is φ = 30006109440.

The previous prime is 81266551577. The next prime is 81266551627. The reversal of 81266551600 is 615566218.

It is a Harshad number since it is a multiple of its sum of digits (40).

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, 7808892 + ... + 7819291.

Almost surely, 2^81266551600 is an apocalyptic number.

81266551600 is a gapful number since it is divisible by the number (80) formed by its first and last digit.

It is an amenable number.

81266551600 is an abundant number, since it is smaller than the sum of its proper divisors (128995035936).

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

81266551600 is a wasteful number, since it uses less digits than its factorization.

81266551600 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 15628214 (or 15628203 counting only the distinct ones).

The product of its (nonzero) digits is 86400, while the sum is 40.

The spelling of 81266551600 in words is "eighty-one billion, two hundred sixty-six million, five hundred fifty-one thousand, six hundred".