81779830 has 32 divisors (see below), whose sum is σ = 164511648. Its totient is φ = 29011200.

The previous prime is 81779813. The next prime is 81779849. The reversal of 81779830 is 3897718.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 4557 + ... + 13576.

It is an arithmetic number, because the mean of its divisors is an integer number (5140989).

Almost surely, 2^81779830 is an apocalyptic number.

81779830 is an abundant number, since it is smaller than the sum of its proper divisors (82731818).

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

81779830 is a wasteful number, since it uses less digits than its factorization.

81779830 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 18192.

The product of its (nonzero) digits is 84672, while the sum is 43.

The square root of 81779830 is about 9043.2201123272. The cubic root of 81779830 is about 434.0589689600.

The spelling of 81779830 in words is "eighty-one million, seven hundred seventy-nine thousand, eight hundred thirty".