21861347 has 6 divisors (see below), whose sum is σ = 22012044. Its totient is φ = 21711500.

The previous prime is 21861341. The next prime is 21861373. The reversal of 21861347 is 74316812.

It is not a de Polignac number, because 21861347 - 2⁶ = 21861283 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (21861341) by changing a digit.

It is a polite number, since it can be written in 5 ways as a sum of consecutive naturals, for example, 62828 + ... + 63174.

It is an arithmetic number, because the mean of its divisors is an integer number (3668674).

Almost surely, 2^21861347 is an apocalyptic number.

21861347 is a deficient number, since it is larger than the sum of its proper divisors (150697).

21861347 is an frugal number, since it uses more digits than its factorization.

21861347 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 849 (or 598 counting only the distinct ones).

The product of its digits is 8064, while the sum is 32.

The square root of 21861347 is about 4675.6119385595. The cubic root of 21861347 is about 279.6140388011.

The spelling of 21861347 in words is "twenty-one million, eight hundred sixty-one thousand, three hundred forty-seven".