1243890 has 64 divisors (see below), whose sum is σ = 3525120. Its totient is φ = 311040.

The previous prime is 1243889. The next prime is 1243927. The reversal of 1243890 is 983421.

It is a Harshad number since it is a multiple of its sum of digits (27).

It is an Ulam number.

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 31 ways as a sum of consecutive naturals, for example, 4455 + ... + 4725.

It is an arithmetic number, because the mean of its divisors is an integer number (55080).

2^1243890 is an apocalyptic number.

1243890 is a gapful number since it is divisible by the number (10) formed by its first and last digit.

It is a practical number, because each smaller number is the sum of distinct divisors of 1243890, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (1762560).

1243890 is an abundant number, since it is smaller than the sum of its proper divisors (2281230).

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

1243890 is a wasteful number, since it uses less digits than its factorization.

1243890 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 304 (or 298 counting only the distinct ones).

The product of its (nonzero) digits is 1728, while the sum is 27.

The square root of 1243890 is about 1115.2981664111. The cubic root of 1243890 is about 107.5459331379.

The spelling of 1243890 in words is "one million, two hundred forty-three thousand, eight hundred ninety".