21513254 has 12 divisors (see below), whose sum is σ = 37538604. Its totient is φ = 9219924.

The previous prime is 21513253. The next prime is 21513259. The reversal of 21513254 is 45231512.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21513251) by changing a digit.

It is a polite number, since it can be written in 5 ways as a sum of consecutive naturals, for example, 109664 + ... + 109859.

It is an arithmetic number, because the mean of its divisors is an integer number (3128217).

Almost surely, 2^21513254 is an apocalyptic number.

21513254 is a deficient number, since it is larger than the sum of its proper divisors (16025350).

21513254 is a wasteful number, since it uses less digits than its factorization.

21513254 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 219539 (or 219532 counting only the distinct ones).

The product of its digits is 1200, while the sum is 23.

The square root of 21513254 is about 4638.2382431264. The cubic root of 21513254 is about 278.1220156899.

Adding to 21513254 its reverse (45231512), we get a palindrome (66744766).

The spelling of 21513254 in words is "twenty-one million, five hundred thirteen thousand, two hundred fifty-four".