1261111621 has 16 divisors (see below), whose sum is σ = 1598076288. Its totient is φ = 966571200.

The previous prime is 1261111609. The next prime is 1261111637.

It is a happy number.

1261111621 is nontrivially palindromic in base 10.

It is not a de Polignac number, because 1261111621 - 2¹³ = 1261103429 is a prime.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 1261111592 and 1261111601.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (1261111121) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 129550 + ... + 138943.

It is an arithmetic number, because the mean of its divisors is an integer number (99879768).

Almost surely, 2^1261111621 is an apocalyptic number.

1261111621 is a gapful number since it is divisible by the number (11) formed by its first and last digit.

It is an amenable number.

1261111621 is a deficient number, since it is larger than the sum of its proper divisors (336964667).

1261111621 is a wasteful number, since it uses less digits than its factorization.

1261111621 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 268572.

The product of its digits is 144, while the sum is 22.

The square root of 1261111621 is about 35512.1334335182. The cubic root of 1261111621 is about 1080.3998350947.

The spelling of 1261111621 in words is "one billion, two hundred sixty-one million, one hundred eleven thousand, six hundred twenty-one".