21461823 has 6 divisors (see below), whose sum is σ = 31000424. Its totient is φ = 14307876.

The previous prime is 21461821. The next prime is 21461831. The reversal of 21461823 is 32816412.

21461823 is a `hidden beast` number, since 21 + 4 + 618 + 23 = 666.

It is not a de Polignac number, because 21461823 - 2¹ = 21461821 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 (21461821) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 5 ways as a sum of consecutive naturals, for example, 1192315 + ... + 1192332.

Almost surely, 2^21461823 is an apocalyptic number.

21461823 is a deficient number, since it is larger than the sum of its proper divisors (9538601).

21461823 is a wasteful number, since it uses less digits than its factorization.

21461823 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2384653 (or 2384650 counting only the distinct ones).

The product of its digits is 2304, while the sum is 27.

The square root of 21461823 is about 4632.6906868471. The cubic root of 21461823 is about 277.9002065775.

It can be divided in two parts, 2146 and 1823, that added together give a square (3969 = 63²).

The spelling of 21461823 in words is "twenty-one million, four hundred sixty-one thousand, eight hundred twenty-three".