21523523 has 8 divisors (see below), whose sum is σ = 25893120. Its totient is φ = 17477640.

The previous prime is 21523519. The next prime is 21523531. The reversal of 21523523 is 32532512.

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

It is a cyclic number.

It is not a de Polignac number, because 21523523 - 2² = 21523519 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (21523543) 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, 80783 + ... + 81048.

It is an arithmetic number, because the mean of its divisors is an integer number (3236640).

Almost surely, 2^21523523 is an apocalyptic number.

21523523 is a deficient number, since it is larger than the sum of its proper divisors (4369597).

21523523 is a wasteful number, since it uses less digits than its factorization.

21523523 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 161857.

The product of its digits is 1800, while the sum is 23.

The square root of 21523523 is about 4639.3451046457. The cubic root of 21523523 is about 278.1662609828.

The spelling of 21523523 in words is "twenty-one million, five hundred twenty-three thousand, five hundred twenty-three".