21611969197 has 32 divisors (see below), whose sum is σ = 28458456320. Its totient is φ = 15933957120.

The previous prime is 21611969179. The next prime is 21611969231. The reversal of 21611969197 is 79196911612.

It is a cyclic number.

It is not a de Polignac number, because 21611969197 - 2⁷ = 21611969069 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21611960197) by changing a digit.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 3013 + ... + 207925.

It is an arithmetic number, because the mean of its divisors is an integer number (889326760).

Almost surely, 2^21611969197 is an apocalyptic number.

It is an amenable number.

21611969197 is a deficient number, since it is larger than the sum of its proper divisors (6846487123).

21611969197 is a wasteful number, since it uses less digits than its factorization.

21611969197 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 205013.

The product of its digits is 367416, while the sum is 52.

The spelling of 21611969197 in words is "twenty-one billion, six hundred eleven million, nine hundred sixty-nine thousand, one hundred ninety-seven".