20400925128187 has 2 divisors, whose sum is σ = 20400925128188. Its totient is φ = 20400925128186.

The previous prime is 20400925128161. The next prime is 20400925128211. The reversal of 20400925128187 is 78182152900402.

It is a happy number.

It is a strong prime.

It is a cyclic number.

It is not a de Polignac number, because 20400925128187 - 2¹¹ = 20400925126139 is a prime.

It is a self number, because there is not a number n which added to its sum of digits gives 20400925128187.

It is not a weakly prime, because it can be changed into another prime (20400925128127) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10200462564093 + 10200462564094.

It is an arithmetic number, because the mean of its divisors is an integer number (10200462564094).

Almost surely, 2^{20400925128187} is an apocalyptic number.

20400925128187 is a deficient number, since it is larger than the sum of its proper divisors (1).

20400925128187 is an equidigital number, since it uses as much as digits as its factorization.

20400925128187 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 645120, while the sum is 49.

The spelling of 20400925128187 in words is "twenty trillion, four hundred billion, nine hundred twenty-five million, one hundred twenty-eight thousand, one hundred eighty-seven".