20390945 has 8 divisors (see below), whose sum is σ = 24494400. Its totient is φ = 16295920.

The previous prime is 20390941. The next prime is 20390947. The reversal of 20390945 is 54909302.

It is a sphenic number, since it is the product of 3 distinct primes.

It is not a de Polignac number, because 20390945 - 2² = 20390941 is a prime.

It is not an unprimeable number, because it can be changed into a prime (20390941) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 6206 + ... + 8904.

It is an arithmetic number, because the mean of its divisors is an integer number (3061800).

Almost surely, 2^20390945 is an apocalyptic number.

It is an amenable number.

20390945 is a deficient number, since it is larger than the sum of its proper divisors (4103455).

20390945 is a wasteful number, since it uses less digits than its factorization.

20390945 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 4215.

The product of its (nonzero) digits is 9720, while the sum is 32.

The square root of 20390945 is about 4515.6333996462. The cubic root of 20390945 is about 273.1990077972.

The spelling of 20390945 in words is "twenty million, three hundred ninety thousand, nine hundred forty-five".