21147848929 has 3 divisors (see below), whose sum is σ = 21147994353. Its totient is φ = 21147703506.

The previous prime is 21147848927. The next prime is 21147848941. The reversal of 21147848929 is 92984874112.

The square root of 21147848929 is 145423.

It is a perfect power (a square), and thus also a powerful number.

It is a semiprime because it is the product of two primes, and also a brilliant number, because the two primes have the same length.

It is not a de Polignac number, because 21147848929 - 2¹ = 21147848927 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 21147848929.

It is not an unprimeable number, because it can be changed into a prime (21147848927) by changing a digit.

It is a polite number, since it can be written in 2 ways as a sum of consecutive naturals, for example, 72712 + ... + 218134.

It is an arithmetic number, because the mean of its divisors is an integer number (7049331451).

Almost surely, 2^21147848929 is an apocalyptic number.

21147848929 is the 145423-rd square number.

21147848929 is the 72712-nd centered octagonal number.

It is an amenable number.

21147848929 is a deficient number, since it is larger than the sum of its proper divisors (145424).

21147848929 is an frugal number, since it uses more digits than its factorization.

21147848929 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 290846 (or 145423 counting only the distinct ones).

The product of its digits is 2322432, while the sum is 55.

The spelling of 21147848929 in words is "twenty-one billion, one hundred forty-seven million, eight hundred forty-eight thousand, nine hundred twenty-nine".