21713479 has 2 divisors, whose sum is σ = 21713480. Its totient is φ = 21713478.

The previous prime is 21713473. The next prime is 21713491. The reversal of 21713479 is 97431712.

It is a weak prime.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-21713479 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (21713473) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10856739 + 10856740.

It is an arithmetic number, because the mean of its divisors is an integer number (10856740).

Almost surely, 2^21713479 is an apocalyptic number.

21713479 is a deficient number, since it is larger than the sum of its proper divisors (1).

21713479 is an equidigital number, since it uses as much as digits as its factorization.

21713479 is an evil number, because the sum of its binary digits is even.

The product of its digits is 10584, while the sum is 34.

The square root of 21713479 is about 4659.7724193355. The cubic root of 21713479 is about 278.9821847713.

It can be divided in two parts, 2 and 1713479, that added together give a square (1713481 = 1309²).

The spelling of 21713479 in words is "twenty-one million, seven hundred thirteen thousand, four hundred seventy-nine".