21729571963 has 4 divisors (see below), whose sum is σ = 23704987608. Its totient is φ = 19754156320.

The previous prime is 21729571957. The next prime is 21729571979. The reversal of 21729571963 is 36917592712.

It is a semiprime because it is the product of two primes.

It is a cyclic number.

It is not a de Polignac number, because 21729571963 - 2¹³ = 21729563771 is a prime.

It is a Duffinian number.

It is a self number, because there is not a number n which added to its sum of digits gives 21729571963.

It is not an unprimeable number, because it can be changed into a prime (21729571943) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 987707806 + ... + 987707827.

It is an arithmetic number, because the mean of its divisors is an integer number (5926246902).

Almost surely, 2^21729571963 is an apocalyptic number.

21729571963 is a deficient number, since it is larger than the sum of its proper divisors (1975415645).

21729571963 is a wasteful number, since it uses less digits than its factorization.

21729571963 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1975415644.

The product of its digits is 1428840, while the sum is 52.

The spelling of 21729571963 in words is "twenty-one billion, seven hundred twenty-nine million, five hundred seventy-one thousand, nine hundred sixty-three".