123621640 has 32 divisors (see below), whose sum is σ = 279207000. Its totient is φ = 49260544.

The previous prime is 123621629. The next prime is 123621647. The reversal of 123621640 is 46126321.

It can be written as a sum of positive squares in 4 ways, for example, as 51065316 + 72556324 = 7146^2 + 8518^2 .

It is not an unprimeable number, because it can be changed into a prime (123621647) 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, 5016 + ... + 16504.

Almost surely, 2^123621640 is an apocalyptic number.

123621640 is a gapful number since it is divisible by the number (10) formed by its first and last digit.

It is an amenable number.

123621640 is an abundant number, since it is smaller than the sum of its proper divisors (155585360).

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

123621640 is a wasteful number, since it uses less digits than its factorization.

123621640 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 11769 (or 11765 counting only the distinct ones).

The product of its (nonzero) digits is 1728, while the sum is 25.

The square root of 123621640 is about 11118.5268808417. The cubic root of 123621640 is about 498.1553898621.

Adding to 123621640 its reverse (46126321), we get a palindrome (169747961).

The spelling of 123621640 in words is "one hundred twenty-three million, six hundred twenty-one thousand, six hundred forty".