21384506 has 16 divisors (see below), whose sum is σ = 37685088. Its totient is φ = 8972400.

The previous prime is 21384479. The next prime is 21384509. The reversal of 21384506 is 60548312.

It is not an unprimeable number, because it can be changed into a prime (21384509) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 37100 + ... + 37671.

It is an arithmetic number, because the mean of its divisors is an integer number (2355318).

Almost surely, 2^21384506 is an apocalyptic number.

21384506 is a gapful number since it is divisible by the number (26) formed by its first and last digit.

21384506 is a deficient number, since it is larger than the sum of its proper divisors (16300582).

21384506 is a wasteful number, since it uses less digits than its factorization.

21384506 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 74797.

The product of its (nonzero) digits is 5760, while the sum is 29.

The square root of 21384506 is about 4624.3384391716. The cubic root of 21384506 is about 277.5660898237.

The spelling of 21384506 in words is "twenty-one million, three hundred eighty-four thousand, five hundred six".