21211002109 has 16 divisors (see below), whose sum is σ = 24150639744. Its totient is φ = 18440294400.

The previous prime is 21211002103. The next prime is 21211002181. The reversal of 21211002109 is 90120011212.

It is a happy number.

It is not a de Polignac number, because 21211002109 - 2²³ = 21202613501 is a prime.

It is a super-2 number, since 2×21211002109² (a number of 21 digits) contains 22 as substring.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21211002103) 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, 2059597 + ... + 2069869.

It is an arithmetic number, because the mean of its divisors is an integer number (1509414984).

Almost surely, 2^21211002109 is an apocalyptic number.

It is an amenable number.

21211002109 is a deficient number, since it is larger than the sum of its proper divisors (2939637635).

21211002109 is a wasteful number, since it uses less digits than its factorization.

21211002109 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 18468.

The product of its (nonzero) digits is 72, while the sum is 19.

The spelling of 21211002109 in words is "twenty-one billion, two hundred eleven million, two thousand, one hundred nine".