21450425 has 12 divisors (see below), whose sum is σ = 27102060. Its totient is φ = 16835520.

The previous prime is 21450389. The next prime is 21450431. The reversal of 21450425 is 52405412.

It is a happy number.

It can be written as a sum of positive squares in 6 ways, for example, as 32041 + 21418384 = 179^2 + 4628^2 .

It is not a de Polignac number, because 21450425 - 2¹² = 21446329 is a prime.

It is a self number, because there is not a number n which added to its sum of digits gives 21450425.

It is an unprimeable number.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 6770 + ... + 9419.

It is an arithmetic number, because the mean of its divisors is an integer number (2258505).

Almost surely, 2^21450425 is an apocalyptic number.

21450425 is a gapful number since it is divisible by the number (25) formed by its first and last digit.

It is an amenable number.

21450425 is a deficient number, since it is larger than the sum of its proper divisors (5651635).

21450425 is a wasteful number, since it uses less digits than its factorization.

21450425 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 16252 (or 16247 counting only the distinct ones).

The product of its (nonzero) digits is 1600, while the sum is 23.

The square root of 21450425 is about 4631.4603528477. The cubic root of 21450425 is about 277.8510018811.

Adding to 21450425 its reverse (52405412), we get a palindrome (73855837).

The spelling of 21450425 in words is "twenty-one million, four hundred fifty thousand, four hundred twenty-five".