1000221121261 has 2 divisors, whose sum is σ = 1000221121262. Its totient is φ = 1000221121260.

The previous prime is 1000221121243. The next prime is 1000221121267. The reversal of 1000221121261 is 1621211220001.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 753901475625 + 246319645636 = 868275^2 + 496306^2 .

It is a cyclic number.

It is not a de Polignac number, because 1000221121261 - 2²³ = 1000212732653 is a prime.

It is a super-2 number, since 2×1000221121261² (a number of 25 digits) contains 22 as substring.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (1000221121267) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 500110560630 + 500110560631.

It is an arithmetic number, because the mean of its divisors is an integer number (500110560631).

Almost surely, 2^{1000221121261} is an apocalyptic number.

It is an amenable number.

1000221121261 is a deficient number, since it is larger than the sum of its proper divisors (1).

1000221121261 is an equidigital number, since it uses as much as digits as its factorization.

1000221121261 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 96, while the sum is 19.

Adding to 1000221121261 its reverse (1621211220001), we get a palindrome (2621432341262).

The spelling of 1000221121261 in words is "one trillion, two hundred twenty-one million, one hundred twenty-one thousand, two hundred sixty-one".