81123658 has 16 divisors (see below), whose sum is σ = 151712064. Its totient is φ = 31606560.

The previous prime is 81123649. The next prime is 81123703. The reversal of 81123658 is 85632118.

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, 263235 + ... + 263542.

It is an arithmetic number, because the mean of its divisors is an integer number (9482004).

Almost surely, 2^81123658 is an apocalyptic number.

81123658 is a deficient number, since it is larger than the sum of its proper divisors (70588406).

81123658 is a wasteful number, since it uses less digits than its factorization.

81123658 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 526797.

The product of its digits is 11520, while the sum is 34.

The square root of 81123658 is about 9006.8672689232. The cubic root of 81123658 is about 432.8949390152.

The spelling of 81123658 in words is "eighty-one million, one hundred twenty-three thousand, six hundred fifty-eight".