21634555444 has 12 divisors (see below), whose sum is σ = 38783898468. Its totient is φ = 10553441600.

The previous prime is 21634555433. The next prime is 21634555451. The reversal of 21634555444 is 44455543612.

It can be written as a sum of positive squares in 2 ways, for example, as 4633524900 + 17001030544 = 68070^2 + 130388^2 .

It is a self number, because there is not a number n which added to its sum of digits gives 21634555444.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 65958847 + ... + 65959174.

It is an arithmetic number, because the mean of its divisors is an integer number (3231991539).

Almost surely, 2^21634555444 is an apocalyptic number.

It is an amenable number.

21634555444 is a deficient number, since it is larger than the sum of its proper divisors (17149343024).

21634555444 is a wasteful number, since it uses less digits than its factorization.

21634555444 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 131918066 (or 131918064 counting only the distinct ones).

The product of its digits is 1152000, while the sum is 43.

The spelling of 21634555444 in words is "twenty-one billion, six hundred thirty-four million, five hundred fifty-five thousand, four hundred forty-four".