81700923890 has 16 divisors (see below), whose sum is σ = 148923204480. Its totient is φ = 32266693680.

The previous prime is 81700923881. The next prime is 81700923907. The reversal of 81700923890 is 9832900718.

It is a Curzon number.

It is an unprimeable number.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 51708656 + ... + 51710235.

It is an arithmetic number, because the mean of its divisors is an integer number (9307700280).

Almost surely, 2^81700923890 is an apocalyptic number.

81700923890 is a deficient number, since it is larger than the sum of its proper divisors (67222280590).

81700923890 is a wasteful number, since it uses less digits than its factorization.

81700923890 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 103418977.

The product of its (nonzero) digits is 217728, while the sum is 47.

The spelling of 81700923890 in words is "eighty-one billion, seven hundred million, nine hundred twenty-three thousand, eight hundred ninety".