21488879 has 4 divisors (see below), whose sum is σ = 22013040. Its totient is φ = 20964720.

The previous prime is 21488839. The next prime is 21488881. The reversal of 21488879 is 97888412.

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 21488879 - 2¹⁶ = 21423343 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 (21488809) 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, 262019 + ... + 262100.

It is an arithmetic number, because the mean of its divisors is an integer number (5503260).

Almost surely, 2^21488879 is an apocalyptic number.

21488879 is a deficient number, since it is larger than the sum of its proper divisors (524161).

21488879 is an equidigital number, since it uses as much as digits as its factorization.

21488879 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 524160.

The product of its digits is 258048, while the sum is 47.

The square root of 21488879 is about 4635.6098843626. The cubic root of 21488879 is about 278.0169364973.

The spelling of 21488879 in words is "twenty-one million, four hundred eighty-eight thousand, eight hundred seventy-nine".