21040120125 has 96 divisors (see below), whose sum is σ = 40531851360. Its totient is φ = 10463385600.

The previous prime is 21040120111. The next prime is 21040120139. The reversal of 21040120125 is 52102104012.

It is an interprime number because it is at equal distance from previous prime (21040120111) and next prime (21040120139).

It can be written as a sum of positive squares in 16 ways, for example, as 9660137796 + 11379982329 = 98286^2 + 106677^2 .

It is not a de Polignac number, because 21040120125 - 2⁵ = 21040120093 is a prime.

It is a junction number, because it is equal to n+sod(n) for n = 21040120098 and 21040120107.

It is a congruent number.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 95 ways as a sum of consecutive naturals, for example, 2079579 + ... + 2089671.

It is an arithmetic number, because the mean of its divisors is an integer number (422206785).

Almost surely, 2^21040120125 is an apocalyptic number.

21040120125 is a gapful number since it is divisible by the number (25) formed by its first and last digit.

It is an amenable number.

21040120125 is a deficient number, since it is larger than the sum of its proper divisors (19491731235).

21040120125 is a wasteful number, since it uses less digits than its factorization.

21040120125 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 10240 (or 10227 counting only the distinct ones).

The product of its (nonzero) digits is 160, while the sum is 18.

Adding to 21040120125 its reverse (52102104012), we get a palindrome (73142224137).

The spelling of 21040120125 in words is "twenty-one billion, forty million, one hundred twenty thousand, one hundred twenty-five".