1261177951 has 4 divisors (see below), whose sum is σ = 1375830504. Its totient is φ = 1146525400.

The previous prime is 1261177949. The next prime is 1261177961. The reversal of 1261177951 is 1597711621.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 1597711621 = 11 ⋅145246511.

It is a cyclic number.

It is not a de Polignac number, because 1261177951 - 2¹ = 1261177949 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (1261177901) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 57326260 + ... + 57326281.

It is an arithmetic number, because the mean of its divisors is an integer number (343957626).

Almost surely, 2^1261177951 is an apocalyptic number.

1261177951 is a gapful number since it is divisible by the number (11) formed by its first and last digit.

1261177951 is a deficient number, since it is larger than the sum of its proper divisors (114652553).

1261177951 is a wasteful number, since it uses less digits than its factorization.

1261177951 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 114652552.

The product of its digits is 26460, while the sum is 40.

The square root of 1261177951 is about 35513.0673273937. The cubic root of 1261177951 is about 1080.4187764962.

The spelling of 1261177951 in words is "one billion, two hundred sixty-one million, one hundred seventy-seven thousand, nine hundred fifty-one".