21749025 has 12 divisors (see below), whose sum is σ = 35958512. Its totient is φ = 11599440.

The previous prime is 21749023. The next prime is 21749029. The reversal of 21749025 is 52094712.

It is not a de Polignac number, because 21749025 - 2¹ = 21749023 is a prime.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 21748983 and 21749001.

It is not an unprimeable number, because it can be changed into a prime (21749023) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 144919 + ... + 145068.

Almost surely, 2^21749025 is an apocalyptic number.

21749025 is a gapful number since it is divisible by the number (25) formed by its first and last digit.

It is an amenable number.

21749025 is a deficient number, since it is larger than the sum of its proper divisors (14209487).

21749025 is a wasteful number, since it uses less digits than its factorization.

21749025 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 290000 (or 289995 counting only the distinct ones).

The product of its (nonzero) digits is 5040, while the sum is 30.

The square root of 21749025 is about 4663.5849944008. The cubic root of 21749025 is about 279.1343374854.

The spelling of 21749025 in words is "twenty-one million, seven hundred forty-nine thousand, twenty-five".