21490425 has 72 divisors (see below), whose sum is σ = 44297760. Its totient is φ = 9849600.

The previous prime is 21490423. The next prime is 21490429. The reversal of 21490425 is 52409412.

It is not a de Polignac number, because 21490425 - 2¹ = 21490423 is a prime.

It is not an unprimeable number, because it can be changed into a prime (21490423) by changing a digit.

It is a polite number, since it can be written in 71 ways as a sum of consecutive naturals, for example, 46797 + ... + 47253.

Almost surely, 2^21490425 is an apocalyptic number.

21490425 is a gapful number since it is divisible by the number (25) formed by its first and last digit.

It is an amenable number.

21490425 is an abundant number, since it is smaller than the sum of its proper divisors (22807335).

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

21490425 is a wasteful number, since it uses less digits than its factorization.

21490425 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 503 (or 495 counting only the distinct ones).

The product of its (nonzero) digits is 2880, while the sum is 27.

The square root of 21490425 is about 4635.7766339633. The cubic root of 21490425 is about 278.0236035719.

Adding to 21490425 its reverse (52409412), we get a palindrome (73899837).

The spelling of 21490425 in words is "twenty-one million, four hundred ninety thousand, four hundred twenty-five".