21713487 has 16 divisors (see below), whose sum is σ = 29913600. Its totient is φ = 13999392.

The previous prime is 21713479. The next prime is 21713491. The reversal of 21713487 is 78431712.

It is a happy number.

It is not a de Polignac number, because 21713487 - 2³ = 21713479 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21713407) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 21598 + ... + 22580.

It is an arithmetic number, because the mean of its divisors is an integer number (1869600).

Almost surely, 2^21713487 is an apocalyptic number.

21713487 is a deficient number, since it is larger than the sum of its proper divisors (8200113).

21713487 is a wasteful number, since it uses less digits than its factorization.

21713487 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1222.

The product of its digits is 9408, while the sum is 33.

The square root of 21713487 is about 4659.7732777465. The cubic root of 21713487 is about 278.9822190336.

The spelling of 21713487 in words is "twenty-one million, seven hundred thirteen thousand, four hundred eighty-seven".