21002542140 has 48 divisors (see below), whose sum is σ = 59916695328. Its totient is φ = 5495003904.

The previous prime is 21002542117. The next prime is 21002542189. The reversal of 21002542140 is 4124520012.

It is a super-2 number, since 2×21002542140² (a number of 21 digits) contains 22 as substring.

It is a congruent number.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 3299107 + ... + 3305466.

It is an arithmetic number, because the mean of its divisors is an integer number (1248264486).

Almost surely, 2^21002542140 is an apocalyptic number.

21002542140 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

21002542140 is an abundant number, since it is smaller than the sum of its proper divisors (38914153188).

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

21002542140 is a wasteful number, since it uses less digits than its factorization.

21002542140 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 6604638 (or 6604636 counting only the distinct ones).

The product of its (nonzero) digits is 640, while the sum is 21.

The spelling of 21002542140 in words is "twenty-one billion, two million, five hundred forty-two thousand, one hundred forty".