1261306215 has 64 divisors (see below), whose sum is σ = 2434252800. Its totient is φ = 615952512.

The previous prime is 1261306199. The next prime is 1261306219. The reversal of 1261306215 is 5126031621.

1261306215 is a `hidden beast` number, since 1 + 2 + 6 + 1 + 30 + 621 + 5 = 666.

It is not a de Polignac number, because 1261306215 - 2⁴ = 1261306199 is a prime.

It is a Harshad number since it is a multiple of its sum of digits (27).

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (1261306219) by changing a digit.

It is a polite number, since it can be written in 63 ways as a sum of consecutive naturals, for example, 220056 + ... + 225714.

It is an arithmetic number, because the mean of its divisors is an integer number (38035200).

Almost surely, 2^1261306215 is an apocalyptic number.

1261306215 is a gapful number since it is divisible by the number (15) formed by its first and last digit.

1261306215 is a deficient number, since it is larger than the sum of its proper divisors (1172946585).

1261306215 is a wasteful number, since it uses less digits than its factorization.

1261306215 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 5813 (or 5807 counting only the distinct ones).

The product of its (nonzero) digits is 2160, while the sum is 27.

The square root of 1261306215 is about 35514.8731519627. The cubic root of 1261306215 is about 1080.4554020801.

Adding to 1261306215 its reverse (5126031621), we get a palindrome (6387337836).

The spelling of 1261306215 in words is "one billion, two hundred sixty-one million, three hundred six thousand, two hundred fifteen".