20749984 has 12 divisors (see below), whose sum is σ = 40851594. Its totient is φ = 10374976.

The previous prime is 20749969. The next prime is 20749987. The reversal of 20749984 is 48994702.

It can be written as a sum of positive squares in only one way, i.e., 20611600 + 138384 = 4540^2 + 372^2 .

It is a self number, because there is not a number n which added to its sum of digits gives 20749984.

It is not an unprimeable number, because it can be changed into a prime (20749987) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 324187 + ... + 324250.

Almost surely, 2^20749984 is an apocalyptic number.

It is an amenable number.

20749984 is a deficient number, since it is larger than the sum of its proper divisors (20101610).

20749984 is an equidigital number, since it uses as much as digits as its factorization.

20749984 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 648447 (or 648439 counting only the distinct ones).

The product of its (nonzero) digits is 145152, while the sum is 43.

The square root of 20749984 is about 4555.2150333437. The cubic root of 20749984 is about 274.7931623751.

The spelling of 20749984 in words is "twenty million, seven hundred forty-nine thousand, nine hundred eighty-four".