81641358 has 20 divisors (see below), whose sum is σ = 182937480. Its totient is φ = 27213732.

The previous prime is 81641333. The next prime is 81641369. The reversal of 81641358 is 85314618.

81641358 is a `hidden beast` number, since 8 + 1 + 641 + 3 + 5 + 8 = 666.

It is a super-2 number, since 2×81641358² = 13330622672168328, which contains 22 as substring.

It is a hoax number, since the sum of its digits (36) coincides with the sum of the digits of its distinct prime factors.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 9 ways as a sum of consecutive naturals, for example, 251818 + ... + 252141.

It is an arithmetic number, because the mean of its divisors is an integer number (9146874).

Almost surely, 2^81641358 is an apocalyptic number.

81641358 is an abundant number, since it is smaller than the sum of its proper divisors (101296122).

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

81641358 is a wasteful number, since it uses less digits than its factorization.

81641358 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 503973 (or 503964 counting only the distinct ones).

The product of its digits is 23040, while the sum is 36.

The square root of 81641358 is about 9035.5607462957. The cubic root of 81641358 is about 433.8138434429.

The spelling of 81641358 in words is "eighty-one million, six hundred forty-one thousand, three hundred fifty-eight".