21187786761189 has 32 divisors (see below), whose sum is σ = 33239315571840. Its totient is φ = 13292868923136.

The previous prime is 21187786761187. The next prime is 21187786761191. The reversal of 21187786761189 is 98116768778112.

It is an interprime number because it is at equal distance from previous prime (21187786761187) and next prime (21187786761191).

It is not a de Polignac number, because 21187786761189 - 2¹ = 21187786761187 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21187786761181) 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, 1803619 + ... + 6754895.

It is an arithmetic number, because the mean of its divisors is an integer number (1038728611620).

Almost surely, 2^{21187786761189} is an apocalyptic number.

It is an amenable number.

21187786761189 is a deficient number, since it is larger than the sum of its proper divisors (12051528810651).

21187786761189 is a wasteful number, since it uses less digits than its factorization.

21187786761189 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 4960626 (or 4960620 counting only the distinct ones).

The product of its digits is 113799168, while the sum is 72.

The spelling of 21187786761189 in words is "twenty-one trillion, one hundred eighty-seven billion, seven hundred eighty-six million, seven hundred sixty-one thousand, one hundred eighty-nine".