21102479 has 4 divisors (see below), whose sum is σ = 21113976. Its totient is φ = 21090984.

The previous prime is 21102467. The next prime is 21102481. The reversal of 21102479 is 97420112.

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 is a cyclic number.

It is not a de Polignac number, because 21102479 - 2⁴ = 21102463 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 (21102409) 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, 2309 + ... + 6894.

It is an arithmetic number, because the mean of its divisors is an integer number (5278494).

Almost surely, 2^21102479 is an apocalyptic number.

21102479 is a deficient number, since it is larger than the sum of its proper divisors (11497).

21102479 is an equidigital number, since it uses as much as digits as its factorization.

21102479 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 11496.

The product of its (nonzero) digits is 1008, while the sum is 26.

The square root of 21102479 is about 4593.7434625804. The cubic root of 21102479 is about 276.3404702216.

The spelling of 21102479 in words is "twenty-one million, one hundred two thousand, four hundred seventy-nine".