1023990 has 64 divisors (see below), whose sum is σ = 2799360. Its totient is φ = 237440.

The previous prime is 1023977. The next prime is 1023991. The reversal of 1023990 is 993201.

It is a happy number.

It is a self number, because there is not a number n which added to its sum of digits gives 1023990.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (1023991) by changing a digit.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 9517 + ... + 9623.

It is an arithmetic number, because the mean of its divisors is an integer number (43740).

2^1023990 is an apocalyptic number.

1023990 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 1023990, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (1399680).

1023990 is an abundant number, since it is smaller than the sum of its proper divisors (1775370).

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

1023990 is a wasteful number, since it uses less digits than its factorization.

1023990 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 157.

The product of its (nonzero) digits is 486, while the sum is 24.

The square root of 1023990 is about 1011.9239101830. The cubic root of 1023990 is about 100.7933558861.

The spelling of 1023990 in words is "one million, twenty-three thousand, nine hundred ninety".