1215953856 has 140 divisors (see below), whose sum is σ = 3881950072. Its totient is φ = 374118912.

The previous prime is 1215953821. The next prime is 1215953891. The reversal of 1215953856 is 6583595121.

1215953856 is a `hidden beast` number, since 1 + 2 + 1 + 595 + 3 + 8 + 56 = 666.

It is an interprime number because it is at equal distance from previous prime (1215953821) and next prime (1215953891).

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 19 ways as a sum of consecutive naturals, for example, 58371 + ... + 76413.

Almost surely, 2^1215953856 is an apocalyptic number.

1215953856 is a gapful number since it is divisible by the number (16) 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 1215953856, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (1940975036).

1215953856 is an abundant number, since it is smaller than the sum of its proper divisors (2665996216).

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

1215953856 is a wasteful number, since it uses less digits than its factorization.

1215953856 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 18080 (or 18061 counting only the distinct ones).

The product of its digits is 324000, while the sum is 45.

The square root of 1215953856 is about 34870.5299070720. The cubic root of 1215953856 is about 1067.3471581419.

The spelling of 1215953856 in words is "one billion, two hundred fifteen million, nine hundred fifty-three thousand, eight hundred fifty-six".