21371072640 has 256 divisors, whose sum is σ = 74457584640. Its totient is φ = 5190451200.

The previous prime is 21371072621. The next prime is 21371072659. The reversal of 21371072640 is 4627017312.

It is an interprime number because it is at equal distance from previous prime (21371072621) and next prime (21371072659).

It is an unprimeable number.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 1001280 + ... + 1022400.

It is an arithmetic number, because the mean of its divisors is an integer number (290849940).

Almost surely, 2^21371072640 is an apocalyptic number.

21371072640 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 21371072640, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (37228792320).

21371072640 is an abundant number, since it is smaller than the sum of its proper divisors (53086512000).

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

21371072640 is a wasteful number, since it uses less digits than its factorization.

21371072640 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 21191 (or 21179 counting only the distinct ones).

The product of its (nonzero) digits is 14112, while the sum is 33.

Adding to 21371072640 its reverse (4627017312), we get a palindrome (25998089952).

The spelling of 21371072640 in words is "twenty-one billion, three hundred seventy-one million, seventy-two thousand, six hundred forty".