21213315641 has 24 divisors (see below), whose sum is σ = 24921051624. Its totient is φ = 18003148800.

The previous prime is 21213315631. The next prime is 21213315691. The reversal of 21213315641 is 14651331212.

It can be written as a sum of positive squares in 4 ways, for example, as 274068025 + 20939247616 = 16555^2 + 144704^2 .

It is not a de Polignac number, because 21213315641 - 2¹⁸ = 21213053497 is a prime.

It is a super-3 number, since 3×21213315641³ (a number of 32 digits) contains 333 as substring.

It is not an unprimeable number, because it can be changed into a prime (21213315631) by changing a digit.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 8863541 + ... + 8865933.

It is an arithmetic number, because the mean of its divisors is an integer number (1038377151).

Almost surely, 2^21213315641 is an apocalyptic number.

It is an amenable number.

21213315641 is a deficient number, since it is larger than the sum of its proper divisors (3707735983).

21213315641 is a wasteful number, since it uses less digits than its factorization.

21213315641 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 4121 (or 4114 counting only the distinct ones).

The product of its digits is 4320, while the sum is 29.

Adding to 21213315641 its reverse (14651331212), we get a palindrome (35864646853).

The spelling of 21213315641 in words is "twenty-one billion, two hundred thirteen million, three hundred fifteen thousand, six hundred forty-one".