101571991 has 4 divisors (see below), whose sum is σ = 107546832. Its totient is φ = 95597152.

The previous prime is 101571973. The next prime is 101572001. The reversal of 101571991 is 199175101.

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 101571991 - 2¹³ = 101563799 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 (101571941) 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, 2987395 + ... + 2987428.

It is an arithmetic number, because the mean of its divisors is an integer number (26886708).

Almost surely, 2^101571991 is an apocalyptic number.

101571991 is a deficient number, since it is larger than the sum of its proper divisors (5974841).

101571991 is an equidigital number, since it uses as much as digits as its factorization.

101571991 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 5974840.

The product of its (nonzero) digits is 2835, while the sum is 34.

The square root of 101571991 is about 10078.2930598391. The cubic root of 101571991 is about 466.5784275909.

The spelling of 101571991 in words is "one hundred one million, five hundred seventy-one thousand, nine hundred ninety-one".