21663653025 has 48 divisors (see below), whose sum is σ = 40947379200. Its totient is φ = 9900144960.

The previous prime is 21663653023. The next prime is 21663653101. The reversal of 21663653025 is 52035636612.

It is not a de Polignac number, because 21663653025 - 2¹ = 21663653023 is a prime.

It is not an unprimeable number, because it can be changed into a prime (21663653023) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 47 ways as a sum of consecutive naturals, for example, 2452066 + ... + 2460884.

It is an arithmetic number, because the mean of its divisors is an integer number (853070400).

Almost surely, 2^21663653025 is an apocalyptic number.

21663653025 is a gapful number since it is divisible by the number (25) formed by its first and last digit.

It is an amenable number.

21663653025 is a deficient number, since it is larger than the sum of its proper divisors (19283726175).

21663653025 is a wasteful number, since it uses less digits than its factorization.

21663653025 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 13518 (or 13513 counting only the distinct ones).

The product of its (nonzero) digits is 194400, while the sum is 39.

The spelling of 21663653025 in words is "twenty-one billion, six hundred sixty-three million, six hundred fifty-three thousand, twenty-five".