20749765 has 8 divisors (see below), whose sum is σ = 25369848. Its totient is φ = 16286400.

The previous prime is 20749763. The next prime is 20749777. The reversal of 20749765 is 56794702.

It can be written as a sum of positive squares in 4 ways, for example, as 804609 + 19945156 = 897^2 + 4466^2 .

It is a sphenic number, since it is the product of 3 distinct primes.

It is not a de Polignac number, because 20749765 - 2¹ = 20749763 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 (20749763) 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, 38886 + ... + 39415.

It is an arithmetic number, because the mean of its divisors is an integer number (3171231).

Almost surely, 2^20749765 is an apocalyptic number.

It is an amenable number.

20749765 is a deficient number, since it is larger than the sum of its proper divisors (4620083).

20749765 is an equidigital number, since it uses as much as digits as its factorization.

20749765 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 78359.

The product of its (nonzero) digits is 105840, while the sum is 40.

The square root of 20749765 is about 4555.1909948980. The cubic root of 20749765 is about 274.7921956288.

The spelling of 20749765 in words is "twenty million, seven hundred forty-nine thousand, seven hundred sixty-five".