21002611440 has 40 divisors (see below), whose sum is σ = 65108096208. Its totient is φ = 5600696320.

The previous prime is 21002611429. The next prime is 21002611463. The reversal of 21002611440 is 4411620012.

It is a happy number.

It is a tau number, because it is divible by the number of its divisors (40).

It is a super-2 number, since 2×21002611440² (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 7 ways as a sum of consecutive naturals, for example, 43755201 + ... + 43755680.

Almost surely, 2^21002611440 is an apocalyptic number.

21002611440 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

21002611440 is an abundant number, since it is smaller than the sum of its proper divisors (44105484768).

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

21002611440 is a wasteful number, since it uses less digits than its factorization.

21002611440 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 87510897 (or 87510891 counting only the distinct ones).

The product of its (nonzero) digits is 384, while the sum is 21.

The spelling of 21002611440 in words is "twenty-one billion, two million, six hundred eleven thousand, four hundred forty".