81542625 has 32 divisors (see below), whose sum is σ = 143679744. Its totient is φ = 40928000.

The previous prime is 81542611. The next prime is 81542639. The reversal of 81542625 is 52624518.

It is an interprime number because it is at equal distance from previous prime (81542611) and next prime (81542639).

It is not a de Polignac number, because 81542625 - 2⁷ = 81542497 is a prime.

It is an unprimeable number.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 21 + ... + 12770.

It is an arithmetic number, because the mean of its divisors is an integer number (4489992).

Almost surely, 2^81542625 is an apocalyptic number.

81542625 is a gapful number since it is divisible by the number (85) formed by its first and last digit.

It is an amenable number.

81542625 is a deficient number, since it is larger than the sum of its proper divisors (62137119).

81542625 is a wasteful number, since it uses less digits than its factorization.

81542625 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 12826 (or 12816 counting only the distinct ones).

The product of its digits is 19200, while the sum is 33.

The square root of 81542625 is about 9030.0955144450. The cubic root of 81542625 is about 433.6388952669.

The spelling of 81542625 in words is "eighty-one million, five hundred forty-two thousand, six hundred twenty-five".