81776353408 has 32 divisors (see below), whose sum is σ = 162968562000. Its totient is φ = 40874439936.

The previous prime is 81776353403. The next prime is 81776353429. The reversal of 81776353408 is 80435367718.

It is a tau number, because it is divible by the number of its divisors (32).

It is a super-2 number, since 2×81776353408² (a number of 23 digits) contains 22 as substring.

It is not an unprimeable number, because it can be changed into a prime (81776353403) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 280623 + ... + 492241.

Almost surely, 2^81776353408 is an apocalyptic number.

It is an amenable number.

81776353408 is a deficient number, since it is larger than the sum of its proper divisors (81192208592).

81776353408 is a wasteful number, since it uses less digits than its factorization.

81776353408 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 214652 (or 214640 counting only the distinct ones).

The product of its (nonzero) digits is 3386880, while the sum is 52.

The spelling of 81776353408 in words is "eighty-one billion, seven hundred seventy-six million, three hundred fifty-three thousand, four hundred eight".