21521514 has 32 divisors (see below), whose sum is σ = 51333120. Its totient is φ = 5881392.

The previous prime is 21521503. The next prime is 21521527. The reversal of 21521514 is 41512512.

It is a super-3 number, since 3×21521514³ (a number of 23 digits) contains 333 as substring.

It is a Harshad number since it is a multiple of its sum of digits (21).

It is a Curzon number.

It is an unprimeable number.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 10174 + ... + 12105.

It is an arithmetic number, because the mean of its divisors is an integer number (1604160).

Almost surely, 2^21521514 is an apocalyptic number.

21521514 is an abundant number, since it is smaller than the sum of its proper divisors (29811606).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

21521514 is a wasteful number, since it uses less digits than its factorization.

21521514 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 22314.

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

The square root of 21521514 is about 4639.1285819645. The cubic root of 21521514 is about 278.1576060582.

The spelling of 21521514 in words is "twenty-one million, five hundred twenty-one thousand, five hundred fourteen".