81176921097 has 4 divisors (see below), whose sum is σ = 108235894800. Its totient is φ = 54117947396.

The previous prime is 81176921083. The next prime is 81176921141. The reversal of 81176921097 is 79012967118.

It is a happy number.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4.

It is a cyclic number.

It is not a de Polignac number, because 81176921097 - 2¹⁵ = 81176888329 is a prime.

It is not an unprimeable number, because it can be changed into a prime (81176421097) 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, 13529486847 + ... + 13529486852.

It is an arithmetic number, because the mean of its divisors is an integer number (27058973700).

Almost surely, 2^81176921097 is an apocalyptic number.

It is an amenable number.

81176921097 is a deficient number, since it is larger than the sum of its proper divisors (27058973703).

81176921097 is a wasteful number, since it uses less digits than its factorization.

81176921097 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 27058973702.

The product of its (nonzero) digits is 381024, while the sum is 51.

The spelling of 81176921097 in words is "eighty-one billion, one hundred seventy-six million, nine hundred twenty-one thousand, ninety-seven".