18613890 has 24 divisors (see below), whose sum is σ = 48396348. Its totient is φ = 4963680.

The previous prime is 18613871. The next prime is 18613891. The reversal of 18613890 is 9831681.

It can be written as a sum of positive squares in 2 ways, for example, as 18429849 + 184041 = 4293^2 + 429^2 .

It is a Curzon number.

It is not an unprimeable number, because it can be changed into a prime (18613891) by changing a digit.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 103321 + ... + 103500.

Almost surely, 2^18613890 is an apocalyptic number.

18613890 is a gapful number since it is divisible by the number (10) formed by its first and last digit.

18613890 is an abundant number, since it is smaller than the sum of its proper divisors (29782458).

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

18613890 is a wasteful number, since it uses less digits than its factorization.

18613890 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 206834 (or 206831 counting only the distinct ones).

The product of its (nonzero) digits is 10368, while the sum is 36.

The square root of 18613890 is about 4314.3817633585. The cubic root of 18613890 is about 265.0202429060.

It can be divided in two parts, 18613 and 890, that added together give a triangular number (19503 = T₁₉₇).

The spelling of 18613890 in words is "eighteen million, six hundred thirteen thousand, eight hundred ninety".