21523051 has 8 divisors (see below), whose sum is σ = 23513904. Its totient is φ = 19537920.

The previous prime is 21523049. The next prime is 21523063. The reversal of 21523051 is 15032512.

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 21523051 - 2¹ = 21523049 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (21523001) 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, 11835 + ... + 13531.

It is an arithmetic number, because the mean of its divisors is an integer number (2939238).

Almost surely, 2^21523051 is an apocalyptic number.

21523051 is a deficient number, since it is larger than the sum of its proper divisors (1990853).

21523051 is a wasteful number, since it uses less digits than its factorization.

21523051 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2861.

The product of its (nonzero) digits is 300, while the sum is 19.

The square root of 21523051 is about 4639.2942351181. The cubic root of 21523051 is about 278.1642276193.

Adding to 21523051 its reverse (15032512), we get a palindrome (36555563).

The spelling of 21523051 in words is "twenty-one million, five hundred twenty-three thousand, fifty-one".