11687396221 has 2 divisors, whose sum is σ = 11687396222. Its totient is φ = 11687396220.

The previous prime is 11687396213. The next prime is 11687396239. The reversal of 11687396221 is 12269378611.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 10611884196 + 1075512025 = 103014^2 + 32795^2 .

It is a cyclic number.

It is not a de Polignac number, because 11687396221 - 2³ = 11687396213 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (11687396291) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 5843698110 + 5843698111.

It is an arithmetic number, because the mean of its divisors is an integer number (5843698111).

Almost surely, 2^11687396221 is an apocalyptic number.

It is an amenable number.

11687396221 is a deficient number, since it is larger than the sum of its proper divisors (1).

11687396221 is an equidigital number, since it uses as much as digits as its factorization.

11687396221 is an evil number, because the sum of its binary digits is even.

The product of its digits is 217728, while the sum is 46.

The spelling of 11687396221 in words is "eleven billion, six hundred eighty-seven million, three hundred ninety-six thousand, two hundred twenty-one".