1261405272 has 32 divisors (see below), whose sum is σ = 3165166080. Its totient is φ = 418914720.

The previous prime is 1261405267. The next prime is 1261405279. The reversal of 1261405272 is 2725041621.

It is a super-2 number, since 2×1261405272² = 3182286520458787968, which contains 22 as substring.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (1261405279) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 90468 + ... + 103475.

It is an arithmetic number, because the mean of its divisors is an integer number (98911440).

Almost surely, 2^1261405272 is an apocalyptic number.

1261405272 is a gapful number since it is divisible by the number (12) formed by its first and last digit.

It is an amenable number.

1261405272 is an abundant number, since it is smaller than the sum of its proper divisors (1903760808).

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

1261405272 is a wasteful number, since it uses less digits than its factorization.

1261405272 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 194223 (or 194219 counting only the distinct ones).

The product of its (nonzero) digits is 6720, while the sum is 30.

The square root of 1261405272 is about 35516.2677093188. The cubic root of 1261405272 is about 1080.4836859517.

Adding to 1261405272 its reverse (2725041621), we get a palindrome (3986446893).

The spelling of 1261405272 in words is "one billion, two hundred sixty-one million, four hundred five thousand, two hundred seventy-two".