21123525140 has 24 divisors (see below), whose sum is σ = 44486521800. Its totient is φ = 8425196928.

The previous prime is 21123525127. The next prime is 21123525167. The reversal of 21123525140 is 4152532112.

It can be written as a sum of positive squares in 4 ways, for example, as 8636356624 + 12487168516 = 92932^2 + 111746^2 .

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 7 ways as a sum of consecutive naturals, for example, 1506167 + ... + 1520126.

It is an arithmetic number, because the mean of its divisors is an integer number (1853605075).

Almost surely, 2^21123525140 is an apocalyptic number.

21123525140 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

21123525140 is an abundant number, since it is smaller than the sum of its proper divisors (23362996660).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

21123525140 is a wasteful number, since it uses less digits than its factorization.

21123525140 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 3026651 (or 3026649 counting only the distinct ones).

The product of its (nonzero) digits is 2400, while the sum is 26.

The spelling of 21123525140 in words is "twenty-one billion, one hundred twenty-three million, five hundred twenty-five thousand, one hundred forty".