21401521125 has 32 divisors (see below), whose sum is σ = 36113755392. Its totient is φ = 11253368000.

The previous prime is 21401521109. The next prime is 21401521129. The reversal of 21401521125 is 52112510412.

It is a happy number.

It is not a de Polignac number, because 21401521125 - 2⁴ = 21401521109 is a prime.

It is a junction number, because it is equal to n+sod(n) for n = 21401521095 and 21401521104.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21401521129) by changing a digit.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 375282 + ... + 428531.

It is an arithmetic number, because the mean of its divisors is an integer number (1128554856).

Almost surely, 2^21401521125 is an apocalyptic number.

21401521125 is a gapful number since it is divisible by the number (25) formed by its first and last digit.

It is an amenable number.

21401521125 is a deficient number, since it is larger than the sum of its proper divisors (14712234267).

21401521125 is an equidigital number, since it uses as much as digits as its factorization.

21401521125 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 803902 (or 803892 counting only the distinct ones).

The product of its (nonzero) digits is 800, while the sum is 24.

The spelling of 21401521125 in words is "twenty-one billion, four hundred one million, five hundred twenty-one thousand, one hundred twenty-five".