21258945909 has 16 divisors (see below), whose sum is σ = 31783681600. Its totient is φ = 14042604528.

The previous prime is 21258945821. The next prime is 21258945949. The reversal of 21258945909 is 90954985212.

21258945909 is a `hidden beast` number, since 2 + 1 + 2 + 589 + 4 + 59 + 0 + 9 = 666.

It is not a de Polignac number, because 21258945909 - 2¹⁶ = 21258880373 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21258945949) 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, 3608839 + ... + 3614724.

It is an arithmetic number, because the mean of its divisors is an integer number (1986480100).

Almost surely, 2^21258945909 is an apocalyptic number.

It is an amenable number.

21258945909 is a deficient number, since it is larger than the sum of its proper divisors (10524735691).

21258945909 is a wasteful number, since it uses less digits than its factorization.

21258945909 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 7223681 (or 7223675 counting only the distinct ones).

The product of its (nonzero) digits is 2332800, while the sum is 54.

The spelling of 21258945909 in words is "twenty-one billion, two hundred fifty-eight million, nine hundred forty-five thousand, nine hundred nine".