21215554544 has 10 divisors (see below), whose sum is σ = 41105136960. Its totient is φ = 10607777264.

The previous prime is 21215554543. The next prime is 21215554609. The reversal of 21215554544 is 44545551212.

It is a junction number, because it is equal to n+sod(n) for n = 21215554498 and 21215554507.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21215554543) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 662986064 + ... + 662986095.

It is an arithmetic number, because the mean of its divisors is an integer number (4110513696).

Almost surely, 2^21215554544 is an apocalyptic number.

It is an amenable number.

21215554544 is a deficient number, since it is larger than the sum of its proper divisors (19889582416).

21215554544 is a wasteful number, since it uses less digits than its factorization.

21215554544 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1325972167 (or 1325972161 counting only the distinct ones).

The product of its digits is 160000, while the sum is 38.

The spelling of 21215554544 in words is "twenty-one billion, two hundred fifteen million, five hundred fifty-four thousand, five hundred forty-four".