20616745 has 4 divisors (see below), whose sum is σ = 24740100. Its totient is φ = 16493392.

The previous prime is 20616707. The next prime is 20616749. The reversal of 20616745 is 54761602.

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 10863616 + 9753129 = 3296^2 + 3123^2 .

It is a cyclic number.

It is not a de Polignac number, because 20616745 - 2²¹ = 18519593 is a prime.

It is a Smith number, since the sum of its digits (31) coincides with the sum of the digits of its prime factors. Since it is squarefree, it is also a hoax number.

It is not an unprimeable number, because it can be changed into a prime (20616749) 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, 2061670 + ... + 2061679.

It is an arithmetic number, because the mean of its divisors is an integer number (6185025).

Almost surely, 2^20616745 is an apocalyptic number.

It is an amenable number.

20616745 is a deficient number, since it is larger than the sum of its proper divisors (4123355).

20616745 is an equidigital number, since it uses as much as digits as its factorization.

20616745 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 4123354.

The product of its (nonzero) digits is 10080, while the sum is 31.

The square root of 20616745 is about 4540.5665946003. The cubic root of 20616745 is about 274.2037352014.

The spelling of 20616745 in words is "twenty million, six hundred sixteen thousand, seven hundred forty-five".