21452511 has 4 divisors (see below), whose sum is σ = 28603352. Its totient is φ = 14301672.

The previous prime is 21452507. The next prime is 21452513. The reversal of 21452511 is 11525412.

It is a semiprime because it is the product of two primes.

It is not a de Polignac number, because 21452511 - 2² = 21452507 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21452513) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 3575416 + ... + 3575421.

It is an arithmetic number, because the mean of its divisors is an integer number (7150838).

Almost surely, 2^21452511 is an apocalyptic number.

21452511 is a deficient number, since it is larger than the sum of its proper divisors (7150841).

21452511 is an equidigital number, since it uses as much as digits as its factorization.

21452511 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 7150840.

The product of its digits is 400, while the sum is 21.

The square root of 21452511 is about 4631.6855463211. The cubic root of 21452511 is about 277.8600083601.

Adding to 21452511 its reverse (11525412), we get a palindrome (32977923).

It can be divided in two parts, 2145 and 2511, that added together give a triangular number (4656 = T₉₆).

The spelling of 21452511 in words is "twenty-one million, four hundred fifty-two thousand, five hundred eleven".