80021521 has 4 divisors (see below), whose sum is σ = 84233200. Its totient is φ = 75809844.

The previous prime is 80021519. The next prime is 80021537. The reversal of 80021521 is 12512008.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4.

It is a cyclic number.

It is not a de Polignac number, because 80021521 - 2¹ = 80021519 is a prime.

It is a Harshad number since it is a multiple of its sum of digits (19), and also a Moran number because the ratio is a prime number: 4211659 = 80021521 / (8 + 0 + 0 + 2 + 1 + 5 + 2 + 1).

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (80021021) 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, 2105811 + ... + 2105848.

It is an arithmetic number, because the mean of its divisors is an integer number (21058300).

Almost surely, 2^80021521 is an apocalyptic number.

It is an amenable number.

80021521 is a deficient number, since it is larger than the sum of its proper divisors (4211679).

80021521 is a wasteful number, since it uses less digits than its factorization.

80021521 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 4211678.

The product of its (nonzero) digits is 160, while the sum is 19.

The square root of 80021521 is about 8945.4748895741. The cubic root of 80021521 is about 430.9255725330.

Adding to 80021521 its reverse (12512008), we get a palindrome (92533529).

The spelling of 80021521 in words is "eighty million, twenty-one thousand, five hundred twenty-one".