81896251 has 8 divisors (see below), whose sum is σ = 86289680. Its totient is φ = 77511168.

The previous prime is 81896239. The next prime is 81896263. The reversal of 81896251 is 15269818.

It is an interprime number because it is at equal distance from previous prime (81896239) and next prime (81896263).

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

It is a cyclic number.

It is not a de Polignac number, because 81896251 - 2²⁵ = 48341819 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (81896051) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 37255 + ... + 39391.

It is an arithmetic number, because the mean of its divisors is an integer number (10786210).

Almost surely, 2^81896251 is an apocalyptic number.

81896251 is a deficient number, since it is larger than the sum of its proper divisors (4393429).

81896251 is a wasteful number, since it uses less digits than its factorization.

81896251 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 4173.

The product of its digits is 34560, while the sum is 40.

The square root of 81896251 is about 9049.6547447955. The cubic root of 81896251 is about 434.2648453905.

The spelling of 81896251 in words is "eighty-one million, eight hundred ninety-six thousand, two hundred fifty-one".