21419861 has 4 divisors (see below), whose sum is σ = 21432972. Its totient is φ = 21406752.

The previous prime is 21419857. The next prime is 21419887. The reversal of 21419861 is 16891412.

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

It can be written as a sum of positive squares in 2 ways, for example, as 12117361 + 9302500 = 3481^2 + 3050^2 .

It is a cyclic number.

It is not a de Polignac number, because 21419861 - 2² = 21419857 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21419851) 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, 3686 + ... + 7511.

It is an arithmetic number, because the mean of its divisors is an integer number (5358243).

Almost surely, 2^21419861 is an apocalyptic number.

It is an amenable number.

21419861 is a deficient number, since it is larger than the sum of its proper divisors (13111).

21419861 is a wasteful number, since it uses less digits than its factorization.

21419861 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 13110.

The product of its digits is 3456, while the sum is 32.

The square root of 21419861 is about 4628.1595694185. The cubic root of 21419861 is about 277.7189722569.

The spelling of 21419861 in words is "twenty-one million, four hundred nineteen thousand, eight hundred sixty-one".