1251751312720 has 160 divisors (see below), whose sum is σ = 3169212434208. Its totient is φ = 457872113664.

The previous prime is 1251751312717. The next prime is 1251751312727. The reversal of 1251751312720 is 272131571521.

It can be written as a sum of positive squares in 16 ways, for example, as 369309013264 + 882442299456 = 607708^2 + 939384^2 .

It is a Harshad number since it is a multiple of its sum of digits (37).

It is a self number, because there is not a number n which added to its sum of digits gives 1251751312720.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (1251751312727) by changing a digit.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 36867592 + ... + 36901528.

Almost surely, 2^{1251751312720} is an apocalyptic number.

1251751312720 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 1251751312720, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (1584606217104).

1251751312720 is an abundant number, since it is smaller than the sum of its proper divisors (1917461121488).

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

1251751312720 is a wasteful number, since it uses less digits than its factorization.

1251751312720 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 34737 (or 34731 counting only the distinct ones).

The product of its (nonzero) digits is 29400, while the sum is 37.

The spelling of 1251751312720 in words is "one trillion, two hundred fifty-one billion, seven hundred fifty-one million, three hundred twelve thousand, seven hundred twenty".