20672945 has 4 divisors (see below), whose sum is σ = 24807540. Its totient is φ = 16538352.

The previous prime is 20672941. The next prime is 20672947. The reversal of 20672945 is 54927602.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 54927602 = 2 ⋅27463801.

It can be written as a sum of positive squares in 2 ways, for example, as 15547249 + 5125696 = 3943^2 + 2264^2 .

It is a cyclic number.

It is not a de Polignac number, because 20672945 - 2² = 20672941 is a prime.

It is not an unprimeable number, because it can be changed into a prime (20672941) 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, 2067290 + ... + 2067299.

It is an arithmetic number, because the mean of its divisors is an integer number (6201885).

Almost surely, 2^20672945 is an apocalyptic number.

It is an amenable number.

20672945 is a deficient number, since it is larger than the sum of its proper divisors (4134595).

20672945 is an equidigital number, since it uses as much as digits as its factorization.

20672945 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 4134594.

The product of its (nonzero) digits is 30240, while the sum is 35.

The square root of 20672945 is about 4546.7510378291. The cubic root of 20672945 is about 274.4526634167.

The spelling of 20672945 in words is "twenty million, six hundred seventy-two thousand, nine hundred forty-five".