81776553156 has 45 divisors (see below), whose sum is σ = 213793520479. Its totient is φ = 27257135256.

The previous prime is 81776553151. The next prime is 81776553217. The reversal of 81776553156 is 65135567718.

It is a happy number.

The square root of 81776553156 is 285966.

It is a perfect power (a square), and thus also a powerful number.

81776553156 is a `hidden beast` number, since 8 + 1 + 7 + 76 + 553 + 15 + 6 = 666.

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

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (81776553151) by changing a digit.

It is a polite number, since it can be written in 14 ways as a sum of consecutive naturals, for example, 5139445 + ... + 5155331.

Almost surely, 2^81776553156 is an apocalyptic number.

81776553156 is the 285966-th square number.

It is an amenable number.

81776553156 is an abundant number, since it is smaller than the sum of its proper divisors (132016967323).

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

81776553156 is an frugal number, since it uses more digits than its factorization.

81776553156 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 31790 (or 15892 counting only the distinct ones).

The product of its digits is 5292000, while the sum is 54.

The spelling of 81776553156 in words is "eighty-one billion, seven hundred seventy-six million, five hundred fifty-three thousand, one hundred fifty-six".