1991879527 has 4 divisors (see below), whose sum is σ = 2172959496. Its totient is φ = 1810799560.

The previous prime is 1991879521. The next prime is 1991879537. The reversal of 1991879527 is 7259781991.

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 1991879527 - 2⁷ = 1991879399 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 (1991879521) 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, 90539968 + ... + 90539989.

It is an arithmetic number, because the mean of its divisors is an integer number (543239874).

Almost surely, 2^1991879527 is an apocalyptic number.

1991879527 is a deficient number, since it is larger than the sum of its proper divisors (181079969).

1991879527 is a wasteful number, since it uses less digits than its factorization.

1991879527 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 181079968.

The product of its digits is 2857680, while the sum is 58.

The square root of 1991879527 is about 44630.4775573822. The cubic root of 1991879527 is about 1258.2135443688.

The spelling of 1991879527 in words is "one billion, nine hundred ninety-one million, eight hundred seventy-nine thousand, five hundred twenty-seven".