1251742378656 has 768 divisors, whose sum is σ = 4411788595200. Its totient is φ = 303495413760.

The previous prime is 1251742378633. The next prime is 1251742378697. The reversal of 1251742378656 is 6568732471521.

It is a happy number.

It is a Harshad number since it is a multiple of its sum of digits (57).

It is a junction number, because it is equal to n+sod(n) for n = 1251742378596 and 1251742378605.

It is an unprimeable number.

It is a polite number, since it can be written in 127 ways as a sum of consecutive naturals, for example, 1240576680 + ... + 1240577688.

It is an arithmetic number, because the mean of its divisors is an integer number (5744516400).

Almost surely, 2^{1251742378656} is an apocalyptic number.

1251742378656 is a gapful number since it is divisible by the number (16) 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 1251742378656, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (2205894297600).

1251742378656 is an abundant number, since it is smaller than the sum of its proper divisors (3160046216544).

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

1251742378656 is a wasteful number, since it uses less digits than its factorization.

1251742378656 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1154 (or 1124 counting only the distinct ones).

The product of its digits is 16934400, while the sum is 57.

The spelling of 1251742378656 in words is "one trillion, two hundred fifty-one billion, seven hundred forty-two million, three hundred seventy-eight thousand, six hundred fifty-six".