91861951 has 4 divisors (see below), whose sum is σ = 92274112. Its totient is φ = 91449792.

The previous prime is 91861921. The next prime is 91861967. The reversal of 91861951 is 15916819.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 15916819 = 937 ⋅16987.

It is a cyclic number.

It is not a de Polignac number, because 91861951 - 2⁵ = 91861919 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (91861921) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 205746 + ... + 206191.

It is an arithmetic number, because the mean of its divisors is an integer number (23068528).

Almost surely, 2^91861951 is an apocalyptic number.

91861951 is a deficient number, since it is larger than the sum of its proper divisors (412161).

91861951 is a wasteful number, since it uses less digits than its factorization.

91861951 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 412160.

The product of its digits is 19440, while the sum is 40.

The square root of 91861951 is about 9584.4640434403. The cubic root of 91861951 is about 451.2098324961.

The spelling of 91861951 in words is "ninety-one million, eight hundred sixty-one thousand, nine hundred fifty-one".