21461646 has 8 divisors (see below), whose sum is σ = 42923304. Its totient is φ = 7153880.

The previous prime is 21461617. The next prime is 21461647. The reversal of 21461646 is 64616412.

It is a sphenic number, since it is the product of 3 distinct primes.

21461646 is an admirable number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21461647) 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, 1788465 + ... + 1788476.

It is an arithmetic number, because the mean of its divisors is an integer number (5365413).

Almost surely, 2^21461646 is an apocalyptic number.

21461646 is a primitive abundant number, since it is smaller than the sum of its proper divisors, none of which is abundant.

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

21461646 is a wasteful number, since it uses less digits than its factorization.

21461646 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 3576946.

The product of its digits is 6912, while the sum is 30.

The square root of 21461646 is about 4632.6715834387. The cubic root of 21461646 is about 277.8994426090.

It can be divided in two parts, 2 and 1461646, that multiplied together give a palindrome (2923292).

The spelling of 21461646 in words is "twenty-one million, four hundred sixty-one thousand, six hundred forty-six".