21450644 has 12 divisors (see below), whose sum is σ = 37749600. Its totient is φ = 10665048.

The previous prime is 21450641. The next prime is 21450647. The reversal of 21450644 is 44605412.

It is an interprime number because it is at equal distance from previous prime (21450641) and next prime (21450647).

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21450641) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 14264 + ... + 15695.

It is an arithmetic number, because the mean of its divisors is an integer number (3145800).

Almost surely, 2^21450644 is an apocalyptic number.

It is an amenable number.

21450644 is a deficient number, since it is larger than the sum of its proper divisors (16298956).

21450644 is a wasteful number, since it uses less digits than its factorization.

21450644 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 30142 (or 30140 counting only the distinct ones).

The product of its (nonzero) digits is 3840, while the sum is 26.

The square root of 21450644 is about 4631.4839954382. The cubic root of 21450644 is about 277.8519474593.

The spelling of 21450644 in words is "twenty-one million, four hundred fifty thousand, six hundred forty-four".