21103211997 has 24 divisors (see below), whose sum is σ = 35778594176. Its totient is φ = 11733058656.

The previous prime is 21103211947. The next prime is 21103211999. The reversal of 21103211997 is 79911230112.

It is not a de Polignac number, because 21103211997 - 2⁸ = 21103211741 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 (21103211999) by changing a digit.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 4524313 + ... + 4528974.

Almost surely, 2^21103211997 is an apocalyptic number.

It is an amenable number.

21103211997 is a deficient number, since it is larger than the sum of its proper divisors (14675382179).

21103211997 is a wasteful number, since it uses less digits than its factorization.

21103211997 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 9053337 (or 9053334 counting only the distinct ones).

The product of its (nonzero) digits is 6804, while the sum is 36.

The spelling of 21103211997 in words is "twenty-one billion, one hundred three million, two hundred eleven thousand, nine hundred ninety-seven".