20902345 has 4 divisors (see below), whose sum is σ = 25082820. Its totient is φ = 16721872.

The previous prime is 20902313. The next prime is 20902381. The reversal of 20902345 is 54320902.

It is a happy number.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 54320902 = 2 ⋅27160451.

It can be written as a sum of positive squares in 2 ways, for example, as 8363664 + 12538681 = 2892^2 + 3541^2 .

It is a cyclic number.

It is not a de Polignac number, because 20902345 - 2⁵ = 20902313 is a prime.

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, 2090230 + ... + 2090239.

It is an arithmetic number, because the mean of its divisors is an integer number (6270705).

Almost surely, 2^20902345 is an apocalyptic number.

It is an amenable number.

20902345 is a deficient number, since it is larger than the sum of its proper divisors (4180475).

20902345 is an equidigital number, since it uses as much as digits as its factorization.

20902345 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 4180474.

The product of its (nonzero) digits is 2160, while the sum is 25.

The square root of 20902345 is about 4571.9082449236. The cubic root of 20902345 is about 275.4640978772.

The spelling of 20902345 in words is "twenty million, nine hundred two thousand, three hundred forty-five".