1231520040 has 96 divisors (see below), whose sum is σ = 4009824000. Its totient is φ = 327799680.

The previous prime is 1231520021. The next prime is 1231520071. The reversal of 1231520040 is 400251321.

It is a Harshad number since it is a multiple of its sum of digits (18).

It is a junction number, because it is equal to n+sod(n) for n = 1231519995 and 1231520022.

It is an unprimeable number.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 212785 + ... + 218495.

It is an arithmetic number, because the mean of its divisors is an integer number (41769000).

Almost surely, 2^1231520040 is an apocalyptic number.

1231520040 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 1231520040, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (2004912000).

1231520040 is an abundant number, since it is smaller than the sum of its proper divisors (2778303960).

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

1231520040 is a wasteful number, since it uses less digits than its factorization.

1231520040 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 6327 (or 6320 counting only the distinct ones).

The product of its (nonzero) digits is 240, while the sum is 18.

The square root of 1231520040 is about 35093.0198187617. The cubic root of 1231520040 is about 1071.8824521181.

Adding to 1231520040 its reverse (400251321), we get a palindrome (1631771361).

The spelling of 1231520040 in words is "one billion, two hundred thirty-one million, five hundred twenty thousand, forty".