81642375 has 48 divisors (see below), whose sum is σ = 151986432. Its totient is φ = 42120000.

The previous prime is 81642361. The next prime is 81642383. The reversal of 81642375 is 57324618.

81642375 is a `hidden beast` number, since 8 + 1 + 642 + 3 + 7 + 5 = 666.

It is not a de Polignac number, because 81642375 - 2⁴ = 81642359 is a prime.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 47 ways as a sum of consecutive naturals, for example, 33705 + ... + 36045.

It is an arithmetic number, because the mean of its divisors is an integer number (3166384).

Almost surely, 2^81642375 is an apocalyptic number.

81642375 is a deficient number, since it is larger than the sum of its proper divisors (70344057).

81642375 is a wasteful number, since it uses less digits than its factorization.

81642375 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2393 (or 2380 counting only the distinct ones).

The product of its digits is 40320, while the sum is 36.

The square root of 81642375 is about 9035.6170237566. The cubic root of 81642375 is about 433.8156447638.

The spelling of 81642375 in words is "eighty-one million, six hundred forty-two thousand, three hundred seventy-five".