1249128720 has 480 divisors, whose sum is σ = 5181096960. Its totient is φ = 263208960.

The previous prime is 1249128697. The next prime is 1249128721. The reversal of 1249128720 is 278219421.

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

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (1249128721) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 95 ways as a sum of consecutive naturals, for example, 5226361 + ... + 5226599.

It is an arithmetic number, because the mean of its divisors is an integer number (10793952).

Almost surely, 2^1249128720 is an apocalyptic number.

1249128720 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 1249128720, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (2590548480).

1249128720 is an abundant number, since it is smaller than the sum of its proper divisors (3931968240).

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

1249128720 is a wasteful number, since it uses less digits than its factorization.

1249128720 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 343 (or 334 counting only the distinct ones).

The product of its (nonzero) digits is 16128, while the sum is 36.

The square root of 1249128720 is about 35343.0151515119. The cubic root of 1249128720 is about 1076.9670047283.

The spelling of 1249128720 in words is "one billion, two hundred forty-nine million, one hundred twenty-eight thousand, seven hundred twenty".