17820949 has 4 divisors (see below), whose sum is σ = 17830540. Its totient is φ = 17811360.

The previous prime is 17820941. The next prime is 17820961. The reversal of 17820949 is 94902871.

It is a semiprime because it is the product of two primes, and also a brilliant number, because the two primes have the same length, and also an emirpimes, since its reverse is a distinct semiprime: 94902871 = 7 ⋅13557553.

It can be written as a sum of positive squares in 2 ways, for example, as 1876900 + 15944049 = 1370^2 + 3993^2 .

It is a cyclic number.

It is not a de Polignac number, because 17820949 - 2³ = 17820941 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (17820941) 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, 1014 + ... + 6055.

It is an arithmetic number, because the mean of its divisors is an integer number (4457635).

Almost surely, 2^17820949 is an apocalyptic number.

It is an amenable number.

17820949 is a deficient number, since it is larger than the sum of its proper divisors (9591).

17820949 is an equidigital number, since it uses as much as digits as its factorization.

17820949 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 9590.

The product of its (nonzero) digits is 36288, while the sum is 40.

The square root of 17820949 is about 4221.4865865001. The cubic root of 17820949 is about 261.2022673261.

It can be divided in two parts, 17820 and 949, that added together give a square (18769 = 137²).

The spelling of 17820949 in words is "seventeen million, eight hundred twenty thousand, nine hundred forty-nine".