1215621240 has 32 divisors (see below), whose sum is σ = 3646864080. Its totient is φ = 324165632.

The previous prime is 1215621221. The next prime is 1215621257. The reversal of 1215621240 is 421265121.

It is a Harshad number since it is a multiple of its sum of digits (24).

It is a self number, because there is not a number n which added to its sum of digits gives 1215621240.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 5064969 + ... + 5065208.

Almost surely, 2^1215621240 is an apocalyptic number.

1215621240 is a gapful number since it is divisible by the number (10) formed by its first and last digit.

It is an amenable number.

1215621240 is an abundant number, since it is smaller than the sum of its proper divisors (2431242840).

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

1215621240 is a wasteful number, since it uses less digits than its factorization.

1215621240 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 10130191 (or 10130187 counting only the distinct ones).

The product of its (nonzero) digits is 960, while the sum is 24.

The square root of 1215621240 is about 34865.7602813993. The cubic root of 1215621240 is about 1067.2498273876.

Adding to 1215621240 its reverse (421265121), we get a palindrome (1636886361).

The spelling of 1215621240 in words is "one billion, two hundred fifteen million, six hundred twenty-one thousand, two hundred forty".