16221386025 has 72 divisors (see below), whose sum is σ = 32448270400. Its totient is φ = 7985874240.

The previous prime is 16221385993. The next prime is 16221386039. The reversal of 16221386025 is 52068312261.

16221386025 is a `hidden beast` number, since 1 + 622 + 1 + 3 + 8 + 6 + 0 + 25 = 666.

It is not a de Polignac number, because 16221386025 - 2⁵ = 16221385993 is a prime.

It is a Curzon number.

It is an unprimeable number.

It is a polite number, since it can be written in 71 ways as a sum of consecutive naturals, for example, 23725 + ... + 181674.

Almost surely, 2^16221386025 is an apocalyptic number.

16221386025 is a gapful number since it is divisible by the number (15) formed by its first and last digit.

It is an amenable number.

16221386025 is an abundant number, since it is smaller than the sum of its proper divisors (16226884375).

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

16221386025 is a wasteful number, since it uses less digits than its factorization.

16221386025 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 205437 (or 205420 counting only the distinct ones).

The product of its (nonzero) digits is 34560, while the sum is 36.

Adding to 16221386025 its reverse (52068312261), we get a palindrome (68289698286).

The spelling of 16221386025 in words is "sixteen billion, two hundred twenty-one million, three hundred eighty-six thousand, twenty-five".