1299392640 has 768 divisors, whose sum is σ = 5756325120. Its totient is φ = 262766592.

The previous prime is 1299392629. The next prime is 1299392641. The reversal of 1299392640 is 462939921.

It is a happy number.

It is a Harshad number since it is a multiple of its sum of digits (45).

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (1299392641) by changing a digit.

It is a polite number, since it can be written in 95 ways as a sum of consecutive naturals, for example, 19393887 + ... + 19393953.

It is an arithmetic number, because the mean of its divisors is an integer number (7495215).

Almost surely, 2^1299392640 is an apocalyptic number.

1299392640 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 1299392640, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (2878162560).

1299392640 is an abundant number, since it is smaller than the sum of its proper divisors (4456932480).

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

1299392640 is a wasteful number, since it uses less digits than its factorization.

1299392640 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 149 (or 134 counting only the distinct ones).

The product of its (nonzero) digits is 209952, while the sum is 45.

The square root of 1299392640 is about 36047.0892028746. The cubic root of 1299392640 is about 1091.2228903332. Note that the first 3 decimals are identical.

The spelling of 1299392640 in words is "one billion, two hundred ninety-nine million, three hundred ninety-two thousand, six hundred forty".