81894915 has 32 divisors (see below), whose sum is σ = 148700160. Its totient is φ = 42744672.

The previous prime is 81894893. The next prime is 81894937. The reversal of 81894915 is 51949818.

81894915 is a `hidden beast` number, since 81 + 89 + 491 + 5 = 666.

It is an interprime number because it is at equal distance from previous prime (81894893) and next prime (81894937).

It is not a de Polignac number, because 81894915 - 2⁶ = 81894851 is a prime.

It is a Harshad number since it is a multiple of its sum of digits (45).

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, 109 + ... + 12798.

It is an arithmetic number, because the mean of its divisors is an integer number (4646880).

Almost surely, 2^81894915 is an apocalyptic number.

81894915 is a deficient number, since it is larger than the sum of its proper divisors (66805245).

81894915 is a wasteful number, since it uses less digits than its factorization.

81894915 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 12968 (or 12962 counting only the distinct ones).

The product of its digits is 103680, while the sum is 45.

The square root of 81894915 is about 9049.5809295238. The cubic root of 81894915 is about 434.2624839434.

The spelling of 81894915 in words is "eighty-one million, eight hundred ninety-four thousand, nine hundred fifteen".