1261001621 has 12 divisors (see below), whose sum is σ = 1392656832. Its totient is φ = 1140909000.

The previous prime is 1261001603. The next prime is 1261001627.

1261001621 is nontrivially palindromic in base 10.

It is not a de Polignac number, because 1261001621 - 2¹⁰ = 1261000597 is a prime.

It is a Duffinian number.

It is a Curzon number.

It is a junction number, because it is equal to n+sod(n) for n = 1261001593 and 1261001602.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (1261001627) by changing a digit.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 836 + ... + 50226.

It is an arithmetic number, because the mean of its divisors is an integer number (116054736).

Almost surely, 2^1261001621 is an apocalyptic number.

1261001621 is a gapful number since it is divisible by the number (11) formed by its first and last digit.

It is an amenable number.

1261001621 is a deficient number, since it is larger than the sum of its proper divisors (131655211).

1261001621 is a wasteful number, since it uses less digits than its factorization.

1261001621 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 49624 (or 49613 counting only the distinct ones).

The product of its (nonzero) digits is 144, while the sum is 20.

The square root of 1261001621 is about 35510.5846333174. The cubic root of 1261001621 is about 1080.3684216878.

It can be divided in two parts, 126100 and 1621, that added together give a palindrome (127721).

The spelling of 1261001621 in words is "one billion, two hundred sixty-one million, one thousand, six hundred twenty-one".