20783749 has 16 divisors (see below), whose sum is σ = 25153920. Its totient is φ = 16793280.

The previous prime is 20783723. The next prime is 20783767. The reversal of 20783749 is 94738702.

It is not a de Polignac number, because 20783749 - 2⁵ = 20783717 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (20783779) 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, 7539 + ... + 9919.

It is an arithmetic number, because the mean of its divisors is an integer number (1572120).

Almost surely, 2^20783749 is an apocalyptic number.

20783749 is a gapful number since it is divisible by the number (29) formed by its first and last digit.

It is an amenable number.

20783749 is a deficient number, since it is larger than the sum of its proper divisors (4370171).

20783749 is a wasteful number, since it uses less digits than its factorization.

20783749 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2460.

The product of its (nonzero) digits is 84672, while the sum is 40.

The square root of 20783749 is about 4558.9197185298. The cubic root of 20783749 is about 274.9421321764.

The spelling of 20783749 in words is "twenty million, seven hundred eighty-three thousand, seven hundred forty-nine".