21866244538 has 8 divisors (see below), whose sum is σ = 32800039488. Its totient is φ = 10932898044.

The previous prime is 21866244527. The next prime is 21866244539. The reversal of 21866244538 is 83544266812.

It is a sphenic number, since it is the product of 3 distinct primes.

It is a super-2 number, since 2×21866244538² (a number of 21 digits) contains 22 as substring.

It is a junction number, because it is equal to n+sod(n) for n = 21866244491 and 21866244500.

It is not an unprimeable number, because it can be changed into a prime (21866244539) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 67045 + ... + 219607.

It is an arithmetic number, because the mean of its divisors is an integer number (4100004936).

Almost surely, 2^21866244538 is an apocalyptic number.

21866244538 is a deficient number, since it is larger than the sum of its proper divisors (10933794950).

21866244538 is a wasteful number, since it uses less digits than its factorization.

21866244538 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 224228.

The product of its digits is 2211840, while the sum is 49.

The spelling of 21866244538 in words is "twenty-one billion, eight hundred sixty-six million, two hundred forty-four thousand, five hundred thirty-eight".