1251767661240 has 128 divisors (see below), whose sum is σ = 3814631884800. Its totient is φ = 328546928640.

The previous prime is 1251767661217. The next prime is 1251767661241. The reversal of 1251767661240 is 421667671521.

It is a self number, because there is not a number n which added to its sum of digits gives 1251767661240.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (1251767661241) 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, 4928481 + ... + 5176239.

It is an arithmetic number, because the mean of its divisors is an integer number (29801811600).

Almost surely, 2^{1251767661240} is an apocalyptic number.

1251767661240 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 1251767661240, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (1907315942400).

1251767661240 is an abundant number, since it is smaller than the sum of its proper divisors (2562864223560).

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

1251767661240 is a wasteful number, since it uses less digits than its factorization.

1251767661240 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 248437 (or 248433 counting only the distinct ones).

The product of its (nonzero) digits is 846720, while the sum is 48.

The spelling of 1251767661240 in words is "one trillion, two hundred fifty-one billion, seven hundred sixty-seven million, six hundred sixty-one thousand, two hundred forty".