83977664521 has 3 divisors (see below), whose sum is σ = 83977954311. Its totient is φ = 83977374732.

The previous prime is 83977664503. The next prime is 83977664527. The reversal of 83977664521 is 12546677938.

The square root of 83977664521 is 289789.

It is a perfect power (a square), and thus also a powerful number.

It is a semiprime because it is the product of two primes, and also a brilliant number, because the two primes have the same length.

It can be written as a sum of positive squares in only one way, i.e., 59921654521 + 24056010000 = 244789^2 + 155100^2 .

It is not a de Polignac number, because 83977664521 - 2¹¹ = 83977662473 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (83977664527) by changing a digit.

It is a polite number, since it can be written in 2 ways as a sum of consecutive naturals, for example, 144895 + ... + 434683.

It is an arithmetic number, because the mean of its divisors is an integer number (27992651437).

Almost surely, 2^83977664521 is an apocalyptic number.

83977664521 is the 289789-th square number.

83977664521 is the 144895-th centered octagonal number.

It is an amenable number.

83977664521 is a deficient number, since it is larger than the sum of its proper divisors (289790).

83977664521 is an frugal number, since it uses more digits than its factorization.

83977664521 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 579578 (or 289789 counting only the distinct ones).

The product of its digits is 15240960, while the sum is 58.

The spelling of 83977664521 in words is "eighty-three billion, nine hundred seventy-seven million, six hundred sixty-four thousand, five hundred twenty-one".