63667840 has 64 divisors (see below), whose sum is σ = 155160360. Its totient is φ = 24973312.

The previous prime is 63667837. The next prime is 63667843. The reversal of 63667840 is 4876636.

It is an interprime number because it is at equal distance from previous prime (63667837) and next prime (63667843).

It can be written as a sum of positive squares in 4 ways, for example, as 58614336 + 5053504 = 7656^2 + 2248^2 .

It is a tau number, because it is divible by the number of its divisors (64).

It is a Harshad number since it is a multiple of its sum of digits (40).

It is a junction number, because it is equal to n+sod(n) for n = 63667793 and 63667802.

It is not an unprimeable number, because it can be changed into a prime (63667843) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 32982 + ... + 34858.

Almost surely, 2^63667840 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 63667840, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (77580180).

63667840 is an abundant number, since it is smaller than the sum of its proper divisors (91492520).

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

63667840 is a wasteful number, since it uses less digits than its factorization.

63667840 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1949 (or 1937 counting only the distinct ones).

The product of its (nonzero) digits is 145152, while the sum is 40.

The square root of 63667840 is about 7979.2129937733. The cubic root of 63667840 is about 399.3067993762.

The spelling of 63667840 in words is "sixty-three million, six hundred sixty-seven thousand, eight hundred forty".