21698479 has 4 divisors (see below), whose sum is σ = 23671080. Its totient is φ = 19725880.

The previous prime is 21698473. The next prime is 21698483. The reversal of 21698479 is 97489612.

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 21698479 - 2²¹ = 19601327 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 (21698473) 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, 986284 + ... + 986305.

It is an arithmetic number, because the mean of its divisors is an integer number (5917770).

Almost surely, 2^21698479 is an apocalyptic number.

21698479 is a deficient number, since it is larger than the sum of its proper divisors (1972601).

21698479 is a wasteful number, since it uses less digits than its factorization.

21698479 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1972600.

The product of its digits is 217728, while the sum is 46.

The square root of 21698479 is about 4658.1626206048. The cubic root of 21698479 is about 278.9179282671.

It can be divided in two parts, 2169 and 8479, that added together give a cube (10648 = 22³).

The spelling of 21698479 in words is "twenty-one million, six hundred ninety-eight thousand, four hundred seventy-nine".