21523137 has 8 divisors (see below), whose sum is σ = 29020320. Its totient is φ = 14187360.

The previous prime is 21523093. The next prime is 21523171. The reversal of 21523137 is 73132512.

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

It is not a de Polignac number, because 21523137 - 2⁸ = 21522881 is a prime.

It is not an unprimeable number, because it can be changed into a prime (21563137) 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, 40039 + ... + 40572.

It is an arithmetic number, because the mean of its divisors is an integer number (3627540).

Almost surely, 2^21523137 is an apocalyptic number.

It is an amenable number.

21523137 is a deficient number, since it is larger than the sum of its proper divisors (7497183).

21523137 is an equidigital number, since it uses as much as digits as its factorization.

21523137 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 80703.

The product of its digits is 1260, while the sum is 24.

The square root of 21523137 is about 4639.3035037600. The cubic root of 21523137 is about 278.1645981073.

Adding to 21523137 its reverse (73132512), we get a palindrome (94655649).

The spelling of 21523137 in words is "twenty-one million, five hundred twenty-three thousand, one hundred thirty-seven".