123521640 has 192 divisors, whose sum is σ = 418279680. Its totient is φ = 29145600.

The previous prime is 123521627. The next prime is 123521659. The reversal of 123521640 is 46125321.

It is a Harshad number since it is a multiple of its sum of digits (24).

It is a self number, because there is not a number n which added to its sum of digits gives 123521640.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 47 ways as a sum of consecutive naturals, for example, 682350 + ... + 682530.

It is an arithmetic number, because the mean of its divisors is an integer number (2178540).

Almost surely, 2^123521640 is an apocalyptic number.

123521640 is a gapful number since it is divisible by the number (10) 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 123521640, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (209139840).

123521640 is an abundant number, since it is smaller than the sum of its proper divisors (294758040).

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

123521640 is a wasteful number, since it uses less digits than its factorization.

123521640 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 264 (or 249 counting only the distinct ones).

The product of its (nonzero) digits is 1440, while the sum is 24.

The square root of 123521640 is about 11114.0289724294. The cubic root of 123521640 is about 498.0210310307.

Adding to 123521640 its reverse (46125321), we get a palindrome (169646961).

The spelling of 123521640 in words is "one hundred twenty-three million, five hundred twenty-one thousand, six hundred forty".