21865746 has 32 divisors (see below), whose sum is σ = 50117760. Its totient is φ = 6230016.

The previous prime is 21865741. The next prime is 21865759. The reversal of 21865746 is 64756812.

It is a super-2 number, since 2×21865746² = 956221696273032, which contains 22 as substring.

It is not an unprimeable number, because it can be changed into a prime (21865741) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 28050 + ... + 28818.

It is an arithmetic number, because the mean of its divisors is an integer number (1566180).

Almost surely, 2^21865746 is an apocalyptic number.

21865746 is an abundant number, since it is smaller than the sum of its proper divisors (28252014).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

21865746 is a wasteful number, since it uses less digits than its factorization.

21865746 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1458.

The product of its digits is 80640, while the sum is 39.

The square root of 21865746 is about 4676.0823346045. The cubic root of 21865746 is about 279.6327924437.

The spelling of 21865746 in words is "twenty-one million, eight hundred sixty-five thousand, seven hundred forty-six".