21500206442 has 96 divisors (see below), whose sum is σ = 40439710080. Its totient is φ = 8450104320.

The previous prime is 21500206421. The next prime is 21500206489. The reversal of 21500206442 is 24460200512.

It is a Harshad number since it is a multiple of its sum of digits (26).

It is an unprimeable number.

It is a polite number, since it can be written in 47 ways as a sum of consecutive naturals, for example, 22233443 + ... + 22234409.

It is an arithmetic number, because the mean of its divisors is an integer number (421246980).

Almost surely, 2^21500206442 is an apocalyptic number.

21500206442 is a gapful number since it is divisible by the number (22) formed by its first and last digit.

21500206442 is a deficient number, since it is larger than the sum of its proper divisors (18939503638).

21500206442 is a wasteful number, since it uses less digits than its factorization.

21500206442 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1296 (or 1279 counting only the distinct ones).

The product of its (nonzero) digits is 3840, while the sum is 26.

Adding to 21500206442 its reverse (24460200512), we get a palindrome (45960406954).

The spelling of 21500206442 in words is "twenty-one billion, five hundred million, two hundred six thousand, four hundred forty-two".