21715573 has 8 divisors (see below), whose sum is σ = 24078816. Its totient is φ = 19417200.

The previous prime is 21715541. The next prime is 21715621. The reversal of 21715573 is 37551712.

It is a sphenic number, since it is the product of 3 distinct primes.

It is not a de Polignac number, because 21715573 - 2⁵ = 21715541 is a prime.

It is a super-2 number, since 2×21715573² = 943132221436658, which contains 22 as substring.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21715873) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 15511 + ... + 16852.

It is an arithmetic number, because the mean of its divisors is an integer number (3009852).

Almost surely, 2^21715573 is an apocalyptic number.

It is an amenable number.

21715573 is a deficient number, since it is larger than the sum of its proper divisors (2363243).

21715573 is a wasteful number, since it uses less digits than its factorization.

21715573 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 32435.

The product of its digits is 7350, while the sum is 31.

The square root of 21715573 is about 4659.9971030034. The cubic root of 21715573 is about 278.9911526252.

It can be divided in two parts, 2171 and 5573, that added together give a square (7744 = 88²).

The spelling of 21715573 in words is "twenty-one million, seven hundred fifteen thousand, five hundred seventy-three".