1251945720 has 192 divisors, whose sum is σ = 4442256000. Its totient is φ = 316234368.

The previous prime is 1251945707. The next prime is 1251945733. The reversal of 1251945720 is 275491521.

It is an interprime number because it is at equal distance from previous prime (1251945707) and next prime (1251945733).

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

It is a congruent number.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 47 ways as a sum of consecutive naturals, for example, 181291 + ... + 188069.

It is an arithmetic number, because the mean of its divisors is an integer number (23136750).

Almost surely, 2^1251945720 is an apocalyptic number.

1251945720 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 1251945720, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (2221128000).

1251945720 is an abundant number, since it is smaller than the sum of its proper divisors (3190310280).

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

1251945720 is a wasteful number, since it uses less digits than its factorization.

1251945720 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 6824 (or 6808 counting only the distinct ones).

The product of its (nonzero) digits is 25200, while the sum is 36.

The square root of 1251945720 is about 35382.8449958451. The cubic root of 1251945720 is about 1077.7759788195.

The spelling of 1251945720 in words is "one billion, two hundred fifty-one million, nine hundred forty-five thousand, seven hundred twenty".