21669312025 has 27 divisors (see below), whose sum is σ = 27387974271. Its totient is φ = 17007476880.

The previous prime is 21669312019. The next prime is 21669312029. The reversal of 21669312025 is 52021396612.

The square root of 21669312025 is 147205.

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., 7800952329 + 13868359696 = 88323^2 + 117764^2 .

It is not a de Polignac number, because 21669312025 - 2³ = 21669312017 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (21669312029) by changing a digit.

It is a polite number, since it can be written in 26 ways as a sum of consecutive naturals, for example, 43425226 + ... + 43425724.

Almost surely, 2^21669312025 is an apocalyptic number.

21669312025 is a gapful number since it is divisible by the number (25) formed by its first and last digit.

21669312025 is the 147205-th square number.

21669312025 is the 73603-rd centered octagonal number.

It is an amenable number.

21669312025 is a deficient number, since it is larger than the sum of its proper divisors (5718662246).

21669312025 is an frugal number, since it uses more digits than its factorization.

21669312025 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1126 (or 563 counting only the distinct ones).

The product of its (nonzero) digits is 38880, while the sum is 37.

The spelling of 21669312025 in words is "twenty-one billion, six hundred sixty-nine million, three hundred twelve thousand, twenty-five".