1251913440 has 96 divisors (see below), whose sum is σ = 3978598176. Its totient is φ = 330874880.

The previous prime is 1251913433. The next prime is 1251913457. The reversal of 1251913440 is 443191521.

It is a tau number, because it is divible by the number of its divisors (96).

It is a super-2 number, since 2×1251913440² = 3134574522505267200, which contains 22 as substring.

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 = 1251913398 and 1251913407.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 42700 + ... + 65780.

It is an arithmetic number, because the mean of its divisors is an integer number (41443731).

Almost surely, 2^1251913440 is an apocalyptic number.

1251913440 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 1251913440, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (1989299088).

1251913440 is an abundant number, since it is smaller than the sum of its proper divisors (2726684736).

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

1251913440 is a wasteful number, since it uses less digits than its factorization.

1251913440 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 23212 (or 23204 counting only the distinct ones).

The product of its (nonzero) digits is 4320, while the sum is 30.

The square root of 1251913440 is about 35382.3888396473. The cubic root of 1251913440 is about 1077.7667156629.

The spelling of 1251913440 in words is "one billion, two hundred fifty-one million, nine hundred thirteen thousand, four hundred forty".