91872155 has 4 divisors (see below), whose sum is σ = 110246592. Its totient is φ = 73497720.

The previous prime is 91872113. The next prime is 91872173. The reversal of 91872155 is 55127819.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 55127819 = 5087 ⋅10837.

It is not a de Polignac number, because 91872155 - 2⁶ = 91872091 is a prime.

It is a super-4 number, since 4×91872155⁴ (a number of 33 digits) contains 4444 as substring.

It is a Duffinian number.

It is an unprimeable number.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 9187211 + ... + 9187220.

It is an arithmetic number, because the mean of its divisors is an integer number (27561648).

Almost surely, 2^91872155 is an apocalyptic number.

91872155 is a deficient number, since it is larger than the sum of its proper divisors (18374437).

91872155 is a wasteful number, since it uses less digits than its factorization.

91872155 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 18374436.

The product of its digits is 25200, while the sum is 38.

The square root of 91872155 is about 9584.9963484604. The cubic root of 91872155 is about 451.2265386318.

The spelling of 91872155 in words is "ninety-one million, eight hundred seventy-two thousand, one hundred fifty-five".