21405233216 has 14 divisors (see below), whose sum is σ = 42476009790. Its totient is φ = 10702616576.

The previous prime is 21405233209. The next prime is 21405233249. The reversal of 21405233216 is 61233250412.

It is a happy number.

It can be written as a sum of positive squares in only one way, i.e., 10816000000 + 10589233216 = 104000^2 + 102904^2 .

It is an unprimeable number.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 167228321 + ... + 167228448.

Almost surely, 2^21405233216 is an apocalyptic number.

It is an amenable number.

21405233216 is a deficient number, since it is larger than the sum of its proper divisors (21070776574).

21405233216 is an equidigital number, since it uses as much as digits as its factorization.

21405233216 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 334456781 (or 334456771 counting only the distinct ones).

The product of its (nonzero) digits is 8640, while the sum is 29.

Adding to 21405233216 its reverse (61233250412), we get a palindrome (82638483628).

The spelling of 21405233216 in words is "twenty-one billion, four hundred five million, two hundred thirty-three thousand, two hundred sixteen".