1251021120 has 224 divisors, whose sum is σ = 4144889856. Its totient is φ = 319334400.

The previous prime is 1251021091. The next prime is 1251021127. The reversal of 1251021120 is 211201521.

It is a Harshad number since it is a multiple of its sum of digits (15).

It is a self number, because there is not a number n which added to its sum of digits gives 1251021120.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (1251021127) 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, 3779355 + ... + 3779685.

Almost surely, 2^1251021120 is an apocalyptic number.

1251021120 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 1251021120, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (2072444928).

1251021120 is an abundant number, since it is smaller than the sum of its proper divisors (2893868736).

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

1251021120 is a wasteful number, since it uses less digits than its factorization.

1251021120 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 509 (or 499 counting only the distinct ones).

The product of its (nonzero) digits is 40, while the sum is 15.

The square root of 1251021120 is about 35369.7769288979. The cubic root of 1251021120 is about 1077.5105900270.

Adding to 1251021120 its reverse (211201521), we get a palindrome (1462222641).

The spelling of 1251021120 in words is "one billion, two hundred fifty-one million, twenty-one thousand, one hundred twenty".