20745390 has 32 divisors (see below), whose sum is σ = 50309280. Its totient is φ = 5474304.

The previous prime is 20745343. The next prime is 20745421. The reversal of 20745390 is 9354702.

It is a Harshad number since it is a multiple of its sum of digits (30).

It is a congruent number.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 655 + ... + 6474.

It is an arithmetic number, because the mean of its divisors is an integer number (1572165).

Almost surely, 2^20745390 is an apocalyptic number.

20745390 is an abundant number, since it is smaller than the sum of its proper divisors (29563890).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

20745390 is a wasteful number, since it uses less digits than its factorization.

20745390 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 7236.

The product of its (nonzero) digits is 7560, while the sum is 30.

The square root of 20745390 is about 4554.7107482254. The cubic root of 20745390 is about 274.7728813480.

The spelling of 20745390 in words is "twenty million, seven hundred forty-five thousand, three hundred ninety".