123655122640 has 80 divisors (see below), whose sum is σ = 342854984448. Its totient is φ = 40552731648.

The previous prime is 123655122623. The next prime is 123655122659. The reversal of 123655122640 is 46221556321.

It is a tau number, because it is divible by the number of its divisors (80).

It is a super-2 number, since 2×123655122640² (a number of 23 digits) contains 22 as substring.

It is a self number, because there is not a number n which added to its sum of digits gives 123655122640.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 4787397 + ... + 4813156.

Almost surely, 2^123655122640 is an apocalyptic number.

123655122640 is a gapful number since it is divisible by the number (10) formed by its first and last digit.

It is an amenable number.

123655122640 is an abundant number, since it is smaller than the sum of its proper divisors (219199861808).

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

123655122640 is a wasteful number, since it uses less digits than its factorization.

123655122640 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 9600596 (or 9600590 counting only the distinct ones).

The product of its (nonzero) digits is 86400, while the sum is 37.

Adding to 123655122640 its reverse (46221556321), we get a palindrome (169876678961).

The spelling of 123655122640 in words is "one hundred twenty-three billion, six hundred fifty-five million, one hundred twenty-two thousand, six hundred forty".