21002192640 has 1296 divisors, whose sum is σ = 92027339040. Its totient is φ = 4379443200.

The previous prime is 21002192633. The next prime is 21002192647. The reversal of 21002192640 is 4629120012.

21002192640 is a `hidden beast` number, since 2 + 1 + 0 + 0 + 2 + 19 + 2 + 640 = 666.

It is an interprime number because it is at equal distance from previous prime (21002192633) and next prime (21002192647).

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21002192647) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 143 ways as a sum of consecutive naturals, for example, 344298210 + ... + 344298270.

Almost surely, 2^21002192640 is an apocalyptic number.

21002192640 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 21002192640, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (46013669520).

21002192640 is an abundant number, since it is smaller than the sum of its proper divisors (71025146400).

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

21002192640 is a wasteful number, since it uses less digits than its factorization.

21002192640 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 142 (or 114 counting only the distinct ones).

The product of its (nonzero) digits is 1728, while the sum is 27.

The spelling of 21002192640 in words is "twenty-one billion, two million, one hundred ninety-two thousand, six hundred forty".