623988 has 18 divisors (see below), whose sum is σ = 1577394. Its totient is φ = 207984.

The previous prime is 623983. The next prime is 623989. The reversal of 623988 is 889326.

It can be written as a sum of positive squares in only one way, i.e., 381924 + 242064 = 618^2 + 492^2 .

It is a tau number, because it is divible by the number of its divisors (18).

It is a super-2 number, since 2×623988² = 778722048288, which contains 22 as substring.

It is a Harshad number since it is a multiple of its sum of digits (36), and also a Moran number because the ratio is a prime number: 17333 = 623988 / (6 + 2 + 3 + 9 + 8 + 8).

It is an Ulam number.

It is a d-powerful number, because it can be written as 6⁶ + 2¹⁹ + 9² + 3⁹ + 8³ + 8⁵ .

It is a plaindrome in base 14.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (623983) by changing a digit.

623988 is an untouchable number, because it is not equal to the sum of proper divisors of any number.

It is a polite number, since it can be written in 5 ways as a sum of consecutive naturals, for example, 8631 + ... + 8702.

It is an arithmetic number, because the mean of its divisors is an integer number (87633).

2⁶²³⁹⁸⁸ is an apocalyptic number.

It is an amenable number.

623988 is an abundant number, since it is smaller than the sum of its proper divisors (953406).

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

623988 is a wasteful number, since it uses less digits than its factorization.

623988 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 17343 (or 17338 counting only the distinct ones).

The product of its digits is 20736, while the sum is 36.

The square root of 623988 is about 789.9291107435. The cubic root of 623988 is about 85.4526258537.

The spelling of 623988 in words is "six hundred twenty-three thousand, nine hundred eighty-eight".