83578991 has 4 divisors (see below), whose sum is σ = 84079632. Its totient is φ = 83078352.

The previous prime is 83578973. The next prime is 83579003. The reversal of 83578991 is 19987538.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 19987538 = 2 ⋅9993769.

It is a cyclic number.

It is not a de Polignac number, because 83578991 - 2⁶ = 83578927 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 (83578931) 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, 250070 + ... + 250403.

It is an arithmetic number, because the mean of its divisors is an integer number (21019908).

Almost surely, 2^83578991 is an apocalyptic number.

83578991 is a deficient number, since it is larger than the sum of its proper divisors (500641).

83578991 is a wasteful number, since it uses less digits than its factorization.

83578991 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 500640.

The product of its digits is 544320, while the sum is 50.

The square root of 83578991 is about 9142.1546147503. The cubic root of 83578991 is about 437.2190147862.

The spelling of 83578991 in words is "eighty-three million, five hundred seventy-eight thousand, nine hundred ninety-one".