21055125123 has 8 divisors (see below), whose sum is σ = 31192778000. Its totient is φ = 14036750064.

The previous prime is 21055125079. The next prime is 21055125131. The reversal of 21055125123 is 32152155012.

21055125123 is a `hidden beast` number, since 21 + 0 + 5 + 512 + 5 + 123 = 666.

It is not a de Polignac number, because 21055125123 - 2¹⁶ = 21055059587 is a prime.

It is a Harshad number since it is a multiple of its sum of digits (27), and also a Moran number because the ratio is a prime number: 779819449 = 21055125123 / (2 + 1 + 0 + 5 + 5 + 1 + 2 + 5 + 1 + 2 + 3).

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (21055125193) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 389909698 + ... + 389909751.

It is an arithmetic number, because the mean of its divisors is an integer number (3899097250).

Almost surely, 2^21055125123 is an apocalyptic number.

21055125123 is a deficient number, since it is larger than the sum of its proper divisors (10137652877).

21055125123 is an equidigital number, since it uses as much as digits as its factorization.

21055125123 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 779819458 (or 779819452 counting only the distinct ones).

The product of its (nonzero) digits is 3000, while the sum is 27.

The spelling of 21055125123 in words is "twenty-one billion, fifty-five million, one hundred twenty-five thousand, one hundred twenty-three".