21969831845 has 18 divisors (see below), whose sum is σ = 28553381298. Its totient is φ = 16220694048.

The previous prime is 21969831811. The next prime is 21969831847. The reversal of 21969831845 is 54813896912.

It can be written as a sum of positive squares in 3 ways, for example, as 103999204 + 21865832641 = 10198^2 + 147871^2 .

It is not a de Polignac number, because 21969831845 - 2¹² = 21969827749 is a prime.

It is a super-2 number, since 2×21969831845² (a number of 21 digits) contains 22 as substring.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21969831847) by changing a digit.

It is a polite number, since it can be written in 17 ways as a sum of consecutive naturals, for example, 4306106 + ... + 4311204.

It is an arithmetic number, because the mean of its divisors is an integer number (1586298961).

Almost surely, 2^21969831845 is an apocalyptic number.

It is an amenable number.

21969831845 is a deficient number, since it is larger than the sum of its proper divisors (6583549453).

21969831845 is an frugal number, since it uses more digits than its factorization.

21969831845 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 10229 (or 5117 counting only the distinct ones).

The product of its digits is 3732480, while the sum is 56.

The spelling of 21969831845 in words is "twenty-one billion, nine hundred sixty-nine million, eight hundred thirty-one thousand, eight hundred forty-five".