83978521 has 8 divisors (see below), whose sum is σ = 97002144. Its totient is φ = 71853120.

The previous prime is 83978513. The next prime is 83978533. The reversal of 83978521 is 12587938.

It is a sphenic number, since it is the product of 3 distinct primes.

It is a cyclic number.

It is not a de Polignac number, because 83978521 - 2³ = 83978513 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (83978561) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 224355 + ... + 224728.

It is an arithmetic number, because the mean of its divisors is an integer number (12125268).

Almost surely, 2^83978521 is an apocalyptic number.

It is an amenable number.

83978521 is a deficient number, since it is larger than the sum of its proper divisors (13023623).

83978521 is a wasteful number, since it uses less digits than its factorization.

83978521 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 449111.

The product of its digits is 120960, while the sum is 43.

The square root of 83978521 is about 9163.9795394796. The cubic root of 83978521 is about 437.9145823576.

The spelling of 83978521 in words is "eighty-three million, nine hundred seventy-eight thousand, five hundred twenty-one".