21299646 has 32 divisors (see below), whose sum is σ = 45077760. Its totient is φ = 6690816.

The previous prime is 21299639. The next prime is 21299647. The reversal of 21299646 is 64699212.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21299647) 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, 28935 + ... + 29661.

It is an arithmetic number, because the mean of its divisors is an integer number (1408680).

Almost surely, 2^21299646 is an apocalyptic number.

21299646 is an abundant number, since it is smaller than the sum of its proper divisors (23778114).

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

21299646 is a wasteful number, since it uses less digits than its factorization.

21299646 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1008.

The product of its digits is 46656, while the sum is 39.

The square root of 21299646 is about 4615.1539519284. The cubic root of 21299646 is about 277.1984485045.

It can be divided in two parts, 21299 and 646, that added together give a triangular number (21945 = T₂₀₉).

The spelling of 21299646 in words is "twenty-one million, two hundred ninety-nine thousand, six hundred forty-six".