21500343512644 has 48 divisors (see below), whose sum is σ = 39887653913856. Its totient is φ = 10119998768000.

The previous prime is 21500343512629. The next prime is 21500343512663. The reversal of 21500343512644 is 44621534300512.

It is a junction number, because it is equal to n+sod(n) for n = 21500343512597 and 21500343512606.

It is an unprimeable number.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 5375947 + ... + 8479474.

It is an arithmetic number, because the mean of its divisors is an integer number (830992789872).

Almost surely, 2^{21500343512644} is an apocalyptic number.

It is an amenable number.

21500343512644 is a deficient number, since it is larger than the sum of its proper divisors (18387310401212).

21500343512644 is a wasteful number, since it uses less digits than its factorization.

21500343512644 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 13855716 (or 13855714 counting only the distinct ones).

The product of its (nonzero) digits is 345600, while the sum is 40.

The spelling of 21500343512644 in words is "twenty-one trillion, five hundred billion, three hundred forty-three million, five hundred twelve thousand, six hundred forty-four".