63865620 has 216 divisors, whose sum is σ = 243125064. Its totient is φ = 13450752.

The previous prime is 63865619. The next prime is 63865649. The reversal of 63865620 is 2656836.

It can be written as a sum of positive squares in 4 ways, for example, as 853776 + 63011844 = 924^2 + 7938^2 .

It is a Harshad number since it is a multiple of its sum of digits (36).

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 71 ways as a sum of consecutive naturals, for example, 114382 + ... + 114938.

It is an arithmetic number, because the mean of its divisors is an integer number (1125579).

Almost surely, 2^63865620 is an apocalyptic number.

63865620 is a gapful number since it is divisible by the number (60) formed by its first and last digit.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 63865620, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (121562532).

63865620 is an abundant number, since it is smaller than the sum of its proper divisors (179259444).

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

63865620 is a wasteful number, since it uses less digits than its factorization.

63865620 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 599 (or 587 counting only the distinct ones).

The product of its (nonzero) digits is 51840, while the sum is 36.

The square root of 63865620 is about 7991.5968366779. The cubic root of 63865620 is about 399.7198454961.

The spelling of 63865620 in words is "sixty-three million, eight hundred sixty-five thousand, six hundred twenty".