20753645749 has 4 divisors (see below), whose sum is σ = 20757784140. Its totient is φ = 20749507360.

The previous prime is 20753645701. The next prime is 20753645771. The reversal of 20753645749 is 94754635702.

It is a happy number.

It is a semiprime because it is the product of two primes.

It can be written as a sum of positive squares in 2 ways, for example, as 13639904100 + 7113741649 = 116790^2 + 84343^2 .

It is a cyclic number.

It is not a de Polignac number, because 20753645749 - 2⁷ = 20753645621 is a prime.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 20753645696 and 20753645705.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (20753645789) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 2061664 + ... + 2071705.

It is an arithmetic number, because the mean of its divisors is an integer number (5189446035).

Almost surely, 2^20753645749 is an apocalyptic number.

It is an amenable number.

20753645749 is a deficient number, since it is larger than the sum of its proper divisors (4138391).

20753645749 is an equidigital number, since it uses as much as digits as its factorization.

20753645749 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 4138390.

The product of its (nonzero) digits is 6350400, while the sum is 52.

The spelling of 20753645749 in words is "twenty billion, seven hundred fifty-three million, six hundred forty-five thousand, seven hundred forty-nine".