21669025 has 45 divisors (see below), whose sum is σ = 33082611. Its totient is φ = 14076720.

The previous prime is 21669019. The next prime is 21669029. The reversal of 21669025 is 52096612.

The square root of 21669025 is 4655.

It is a perfect power (a square), and thus also a powerful number.

It can be written as a sum of positive squares in only one way, i.e., 7800849 + 13868176 = 2793^2 + 3724^2 .

It is not a de Polignac number, because 21669025 - 2³ = 21669017 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (21669029) by changing a digit.

It is a polite number, since it can be written in 44 ways as a sum of consecutive naturals, for example, 1140466 + ... + 1140484.

Almost surely, 2^21669025 is an apocalyptic number.

21669025 is a gapful number since it is divisible by the number (25) formed by its first and last digit.

21669025 is the 4655-th square number.

21669025 is the 2328-th centered octagonal number.

It is an amenable number.

21669025 is a deficient number, since it is larger than the sum of its proper divisors (11413586).

21669025 is an frugal number, since it uses more digits than its factorization.

21669025 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 76 (or 31 counting only the distinct ones).

The product of its (nonzero) digits is 6480, while the sum is 31.

The cubic root of 21669025 is about 278.7916679786.

The spelling of 21669025 in words is "twenty-one million, six hundred sixty-nine thousand, twenty-five".