20261656187 has 2 divisors, whose sum is σ = 20261656188. Its totient is φ = 20261656186.

The previous prime is 20261656139. The next prime is 20261656223. The reversal of 20261656187 is 78165616202.

It is a strong prime.

It is a cyclic number.

It is not a de Polignac number, because 20261656187 - 2⁶ = 20261656123 is a prime.

It is a super-2 number, since 2×20261656187² (a number of 21 digits) contains 22 as substring.

It is not a weakly prime, because it can be changed into another prime (20261656687) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10130828093 + 10130828094.

It is an arithmetic number, because the mean of its divisors is an integer number (10130828094).

Almost surely, 2^20261656187 is an apocalyptic number.

20261656187 is a deficient number, since it is larger than the sum of its proper divisors (1).

20261656187 is an equidigital number, since it uses as much as digits as its factorization.

20261656187 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 241920, while the sum is 44.

The spelling of 20261656187 in words is "twenty billion, two hundred sixty-one million, six hundred fifty-six thousand, one hundred eighty-seven".