21004023243 has 64 divisors (see below), whose sum is σ = 34393669632. Its totient is φ = 11128803840.

The previous prime is 21004023239. The next prime is 21004023263. The reversal of 21004023243 is 34232040012.

It is not a de Polignac number, because 21004023243 - 2² = 21004023239 is a prime.

It is a Harshad number since it is a multiple of its sum of digits (21).

It is not an unprimeable number, because it can be changed into a prime (21004023263) by changing a digit.

It is a polite number, since it can be written in 63 ways as a sum of consecutive naturals, for example, 13718388 + ... + 13719918.

It is an arithmetic number, because the mean of its divisors is an integer number (537401088).

Almost surely, 2^21004023243 is an apocalyptic number.

21004023243 is a deficient number, since it is larger than the sum of its proper divisors (13389646389).

21004023243 is a wasteful number, since it uses less digits than its factorization.

21004023243 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2104.

The product of its (nonzero) digits is 1152, while the sum is 21.

Adding to 21004023243 its reverse (34232040012), we get a palindrome (55236063255).

The spelling of 21004023243 in words is "twenty-one billion, four million, twenty-three thousand, two hundred forty-three".