1251321135240 has 256 divisors, whose sum is σ = 4116668832000. Its totient is φ = 301767065600.

The previous prime is 1251321135187. The next prime is 1251321135277. The reversal of 1251321135240 is 425311231521.

It is a happy number.

It is a Harshad number since it is a multiple of its sum of digits (30).

It is a junction number, because it is equal to n+sod(n) for n = 1251321135198 and 1251321135207.

It is an unprimeable number.

It is a polite number, since it can be written in 63 ways as a sum of consecutive naturals, for example, 209213050 + ... + 209219030.

It is an arithmetic number, because the mean of its divisors is an integer number (16080737625).

Almost surely, 2^{1251321135240} is an apocalyptic number.

1251321135240 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 1251321135240, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (2058334416000).

1251321135240 is an abundant number, since it is smaller than the sum of its proper divisors (2865347696760).

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

1251321135240 is a wasteful number, since it uses less digits than its factorization.

1251321135240 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 6808 (or 6804 counting only the distinct ones).

The product of its (nonzero) digits is 7200, while the sum is 30.

Adding to 1251321135240 its reverse (425311231521), we get a palindrome (1676632366761).

The spelling of 1251321135240 in words is "one trillion, two hundred fifty-one billion, three hundred twenty-one million, one hundred thirty-five thousand, two hundred forty".