20929745 has 4 divisors (see below), whose sum is σ = 25115700. Its totient is φ = 16743792.

The previous prime is 20929729. The next prime is 20929751. The reversal of 20929745 is 54792902.

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 15808576 + 5121169 = 3976^2 + 2263^2 .

It is a cyclic number.

It is not a de Polignac number, because 20929745 - 2⁴ = 20929729 is a prime.

It is a junction number, because it is equal to n+sod(n) for n = 20929699 and 20929708.

It is an unprimeable number.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 2092970 + ... + 2092979.

It is an arithmetic number, because the mean of its divisors is an integer number (6278925).

Almost surely, 2^20929745 is an apocalyptic number.

It is an amenable number.

20929745 is a deficient number, since it is larger than the sum of its proper divisors (4185955).

20929745 is an equidigital number, since it uses as much as digits as its factorization.

20929745 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 4185954.

The product of its (nonzero) digits is 45360, while the sum is 38.

The square root of 20929745 is about 4574.9038241257. The cubic root of 20929745 is about 275.5844100669.

The spelling of 20929745 in words is "twenty million, nine hundred twenty-nine thousand, seven hundred forty-five".