91851009251 has 4 divisors (see below), whose sum is σ = 92521454712. Its totient is φ = 91180563792.

The previous prime is 91851009247. The next prime is 91851009259. The reversal of 91851009251 is 15290015819.

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 91851009251 - 2² = 91851009247 is a prime.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 91851009199 and 91851009208.

It is not an unprimeable number, because it can be changed into a prime (91851009259) 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, 335222525 + ... + 335222798.

It is an arithmetic number, because the mean of its divisors is an integer number (23130363678).

Almost surely, 2^91851009251 is an apocalyptic number.

91851009251 is a deficient number, since it is larger than the sum of its proper divisors (670445461).

91851009251 is a wasteful number, since it uses less digits than its factorization.

91851009251 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 670445460.

The product of its (nonzero) digits is 32400, while the sum is 41.

The spelling of 91851009251 in words is "ninety-one billion, eight hundred fifty-one million, nine thousand, two hundred fifty-one".