86991251 has 4 divisors (see below), whose sum is σ = 87567504. Its totient is φ = 86415000.

The previous prime is 86991211. The next prime is 86991257. The reversal of 86991251 is 15219968.

It is a happy number.

It is a semiprime because it is the product of two primes.

It is a cyclic number.

It is not a de Polignac number, because 86991251 - 2⁶ = 86991187 is a prime.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 86991199 and 86991208.

It is not an unprimeable number, because it can be changed into a prime (86991257) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 287900 + ... + 288201.

It is an arithmetic number, because the mean of its divisors is an integer number (21891876).

Almost surely, 2^86991251 is an apocalyptic number.

86991251 is a deficient number, since it is larger than the sum of its proper divisors (576253).

86991251 is a wasteful number, since it uses less digits than its factorization.

86991251 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 576252.

The product of its digits is 38880, while the sum is 41.

The square root of 86991251 is about 9326.9100456689. The cubic root of 86991251 is about 443.0899083244.

The spelling of 86991251 in words is "eighty-six million, nine hundred ninety-one thousand, two hundred fifty-one".