21523719 has 8 divisors (see below), whose sum is σ = 32798080. Its totient is φ = 12299256.

The previous prime is 21523681. The next prime is 21523727. The reversal of 21523719 is 91732512.

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

It is not a de Polignac number, because 21523719 - 2⁷ = 21523591 is a prime.

It is a super-2 number, since 2×21523719² = 926540959181922, which contains 22 as substring.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21523739) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 512449 + ... + 512490.

It is an arithmetic number, because the mean of its divisors is an integer number (4099760).

Almost surely, 2^21523719 is an apocalyptic number.

21523719 is a deficient number, since it is larger than the sum of its proper divisors (11274361).

21523719 is a wasteful number, since it uses less digits than its factorization.

21523719 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1024949.

The product of its digits is 3780, while the sum is 30.

The square root of 21523719 is about 4639.3662282687. The cubic root of 21523719 is about 278.1671053368.

The spelling of 21523719 in words is "twenty-one million, five hundred twenty-three thousand, seven hundred nineteen".