663961536 has 392 divisors, whose sum is σ = 2398654080. Its totient is φ = 178039296.

The previous prime is 663961531. The next prime is 663961549. The reversal of 663961536 is 635169366.

663961536 is a `hidden beast` number, since 6 + 639 + 6 + 1 + 5 + 3 + 6 = 666.

It is a junction number, because it is equal to n+sod(n) for n = 663961491 and 663961500.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (663961531) by changing a digit.

It is a polite number, since it can be written in 55 ways as a sum of consecutive naturals, for example, 6205195 + ... + 6205301.

Almost surely, 2^663961536 is an apocalyptic number.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 663961536, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (1199327040).

663961536 is an abundant number, since it is smaller than the sum of its proper divisors (1734692544).

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

663961536 is a wasteful number, since it uses less digits than its factorization.

663961536 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 163 (or 138 counting only the distinct ones).

The product of its digits is 524880, while the sum is 45.

The square root of 663961536 is about 25767.4510962959. The cubic root of 663961536 is about 872.3972883144.

The spelling of 663961536 in words is "six hundred sixty-three million, nine hundred sixty-one thousand, five hundred thirty-six".