81872457 has 8 divisors (see below), whose sum is σ = 112684800. Its totient is φ = 52820880.

The previous prime is 81872447. The next prime is 81872467. The reversal of 81872457 is 75427818.

It is an interprime number because it is at equal distance from previous prime (81872447) and next prime (81872467).

It is a sphenic number, since it is the product of 3 distinct primes.

It is not a de Polignac number, because 81872457 - 2¹² = 81868361 is a prime.

It is not an unprimeable number, because it can be changed into a prime (81872437) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 440082 + ... + 440267.

It is an arithmetic number, because the mean of its divisors is an integer number (14085600).

Almost surely, 2^81872457 is an apocalyptic number.

It is an amenable number.

81872457 is a deficient number, since it is larger than the sum of its proper divisors (30812343).

81872457 is a wasteful number, since it uses less digits than its factorization.

81872457 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 880383.

The product of its digits is 125440, while the sum is 42.

The square root of 81872457 is about 9048.3400135052. The cubic root of 81872457 is about 434.2227844558. Note that the first 3 decimals are identical.

The spelling of 81872457 in words is "eighty-one million, eight hundred seventy-two thousand, four hundred fifty-seven".