81630784761 has 8 divisors (see below), whose sum is σ = 109316335680. Its totient is φ = 54182878512.

The previous prime is 81630784747. The next prime is 81630784777. The reversal of 81630784761 is 16748703618.

It is a sphenic number, since it is the product of 3 distinct primes.

It is a de Polignac number, because none of the positive numbers 2^k-81630784761 is a prime.

It is not an unprimeable number, because it can be changed into a prime (81630784561) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 59410365 + ... + 59411738.

It is an arithmetic number, because the mean of its divisors is an integer number (13664541960).

Almost surely, 2^81630784761 is an apocalyptic number.

It is an amenable number.

81630784761 is a deficient number, since it is larger than the sum of its proper divisors (27685550919).

81630784761 is a wasteful number, since it uses less digits than its factorization.

81630784761 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 118822335.

The product of its (nonzero) digits is 1354752, while the sum is 51.

The spelling of 81630784761 in words is "eighty-one billion, six hundred thirty million, seven hundred eighty-four thousand, seven hundred sixty-one".