123999540 has 48 divisors (see below), whose sum is σ = 396799872. Its totient is φ = 28342656.

The previous prime is 123999523. The next prime is 123999541. The reversal of 123999540 is 45999321.

It is a Harshad number since it is a multiple of its sum of digits (42).

It is a junction number, because it is equal to n+sod(n) for n = 123999492 and 123999501.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (123999541) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 147199 + ... + 148038.

It is an arithmetic number, because the mean of its divisors is an integer number (8266664).

Almost surely, 2^123999540 is an apocalyptic number.

123999540 is a gapful number since it is divisible by the number (10) formed by its first and last digit.

It is an amenable number.

123999540 is an abundant number, since it is smaller than the sum of its proper divisors (272800332).

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

123999540 is a wasteful number, since it uses less digits than its factorization.

123999540 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 295256 (or 295254 counting only the distinct ones).

The product of its (nonzero) digits is 87480, while the sum is 42.

The square root of 123999540 is about 11135.5080710312. The cubic root of 123999540 is about 498.6624785967.

The spelling of 123999540 in words is "one hundred twenty-three million, nine hundred ninety-nine thousand, five hundred forty".