21798425 has 24 divisors (see below), whose sum is σ = 30450432. Its totient is φ = 15336000.

The previous prime is 21798421. The next prime is 21798449. The reversal of 21798425 is 52489712.

It is not a de Polignac number, because 21798425 - 2² = 21798421 is a prime.

It is a Curzon number.

It is not an unprimeable number, because it can be changed into a prime (21798421) by changing a digit.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 7247 + ... + 9803.

It is an arithmetic number, because the mean of its divisors is an integer number (1268768).

Almost surely, 2^21798425 is an apocalyptic number.

21798425 is a gapful number since it is divisible by the number (25) formed by its first and last digit.

It is an amenable number.

21798425 is a deficient number, since it is larger than the sum of its proper divisors (8652007).

21798425 is a wasteful number, since it uses less digits than its factorization.

21798425 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2609 (or 2604 counting only the distinct ones).

The product of its digits is 40320, while the sum is 38.

The square root of 21798425 is about 4668.8783449561. The cubic root of 21798425 is about 279.3455164431.

The spelling of 21798425 in words is "twenty-one million, seven hundred ninety-eight thousand, four hundred twenty-five".