20748729 has 4 divisors (see below), whose sum is σ = 27664976. Its totient is φ = 13832484.

The previous prime is 20748727. The next prime is 20748751. The reversal of 20748729 is 92784702.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4.

It is not a de Polignac number, because 20748729 - 2¹ = 20748727 is a prime.

It is a super-5 number, since 5×20748729⁵ (a number of 38 digits) contains 55555 as substring.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (20748727) 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, 3458119 + ... + 3458124.

It is an arithmetic number, because the mean of its divisors is an integer number (6916244).

Almost surely, 2^20748729 is an apocalyptic number.

It is an amenable number.

20748729 is a deficient number, since it is larger than the sum of its proper divisors (6916247).

20748729 is an equidigital number, since it uses as much as digits as its factorization.

20748729 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 6916246.

The product of its (nonzero) digits is 56448, while the sum is 39.

The square root of 20748729 is about 4555.0772770613. The cubic root of 20748729 is about 274.7876222525.

The spelling of 20748729 in words is "twenty million, seven hundred forty-eight thousand, seven hundred twenty-nine".