1866438 has 24 divisors (see below), whose sum is σ = 4621968. Its totient is φ = 533232.

The previous prime is 1866437. The next prime is 1866439. The reversal of 1866438 is 8346681.

It is a happy number.

1866438 is a `hidden beast` number, since 1 + 8 + 6 + 643 + 8 = 666.

It is an interprime number because it is at equal distance from previous prime (1866437) and next prime (1866439).

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (1866437) 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, 7281 + ... + 7532.

It is an arithmetic number, because the mean of its divisors is an integer number (192582).

2^1866438 is an apocalyptic number.

1866438 is a gapful number since it is divisible by the number (18) formed by its first and last digit.

1866438 is an abundant number, since it is smaller than the sum of its proper divisors (2755530).

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

1866438 is a wasteful number, since it uses less digits than its factorization.

1866438 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 14828 (or 14825 counting only the distinct ones).

The product of its digits is 27648, while the sum is 36.

The square root of 1866438 is about 1366.1764161337. The cubic root of 1866438 is about 123.1226221122.

It can be divided in two parts, 1866 and 438, that added together give a square (2304 = 48²).

The spelling of 1866438 in words is "one million, eight hundred sixty-six thousand, four hundred thirty-eight".