21325555209 has 16 divisors (see below), whose sum is σ = 33374357888. Its totient is φ = 11856678912.

The previous prime is 21325555193. The next prime is 21325555231. The reversal of 21325555209 is 90255552312.

It is a happy number.

It is not a de Polignac number, because 21325555209 - 2⁴ = 21325555193 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (21325555249) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 13722232 + ... + 13723785.

It is an arithmetic number, because the mean of its divisors is an integer number (2085897368).

Almost surely, 2^21325555209 is an apocalyptic number.

It is an amenable number.

21325555209 is a deficient number, since it is larger than the sum of its proper divisors (12048802679).

21325555209 is a wasteful number, since it uses less digits than its factorization.

21325555209 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 27446064.

The product of its (nonzero) digits is 135000, while the sum is 39.

The spelling of 21325555209 in words is "twenty-one billion, three hundred twenty-five million, five hundred fifty-five thousand, two hundred nine".