21519025 has 24 divisors (see below), whose sum is σ = 30828384. Its totient is φ = 14726400.

The previous prime is 21518971. The next prime is 21519061. The reversal of 21519025 is 52091512.

It is not a de Polignac number, because 21519025 - 2¹³ = 21510833 is a prime.

It is a Harshad number since it is a multiple of its sum of digits (25).

It is a Duffinian number.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 2374 + ... + 6976.

It is an arithmetic number, because the mean of its divisors is an integer number (1284516).

Almost surely, 2^21519025 is an apocalyptic number.

21519025 is a gapful number since it is divisible by the number (25) formed by its first and last digit.

It is an amenable number.

21519025 is a deficient number, since it is larger than the sum of its proper divisors (9309359).

21519025 is a wasteful number, since it uses less digits than its factorization.

21519025 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 4641 (or 4636 counting only the distinct ones).

The product of its (nonzero) digits is 900, while the sum is 25.

The square root of 21519025 is about 4638.8603126199. The cubic root of 21519025 is about 278.1468825101.

The spelling of 21519025 in words is "twenty-one million, five hundred nineteen thousand, twenty-five".