63990 has 40 divisors (see below), whose sum is σ = 174240. Its totient is φ = 16848.

The previous prime is 63977. The next prime is 63997. The reversal of 63990 is 9936.

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

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (63997) by changing a digit.

It is a polite number, since it can be written in 19 ways as a sum of consecutive naturals, for example, 771 + ... + 849.

It is an arithmetic number, because the mean of its divisors is an integer number (4356).

2⁶³⁹⁹⁰ is an apocalyptic number.

It is a practical number, because each smaller number is the sum of distinct divisors of 63990, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (87120).

63990 is an abundant number, since it is smaller than the sum of its proper divisors (110250).

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

63990 is a wasteful number, since it uses less digits than its factorization.

63990 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 98 (or 89 counting only the distinct ones).

The product of its (nonzero) digits is 1458, while the sum is 27.

The square root of 63990 is about 252.9624478060. The cubic root of 63990 is about 39.9979165582.

It can be divided in two parts, 639 and 90, that added together give a 6-th power (729 = 3⁶).

The spelling of 63990 in words is "sixty-three thousand, nine hundred ninety".