1231478640 has 400 divisors, whose sum is σ = 5178900672. Its totient is φ = 264757248.

The previous prime is 1231478639. The next prime is 1231478669. The reversal of 1231478640 is 468741321.

1231478640 is a `hidden beast` number, since 1 + 2 + 3 + 1 + 4 + 7 + 8 + 640 = 666.

It is a Harshad number since it is a multiple of its sum of digits (36).

It is a junction number, because it is equal to n+sod(n) for n = 1231478595 and 1231478604.

It is a congruent number.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 79 ways as a sum of consecutive naturals, for example, 770322 + ... + 771918.

Almost surely, 2^1231478640 is an apocalyptic number.

1231478640 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 1231478640, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (2589450336).

1231478640 is an abundant number, since it is smaller than the sum of its proper divisors (3947422032).

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

1231478640 is a wasteful number, since it uses less digits than its factorization.

1231478640 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1646 (or 1631 counting only the distinct ones).

The product of its (nonzero) digits is 32256, while the sum is 36.

The square root of 1231478640 is about 35092.4299529115. The cubic root of 1231478640 is about 1071.8704408287.

The spelling of 1231478640 in words is "one billion, two hundred thirty-one million, four hundred seventy-eight thousand, six hundred forty".