1211421657601 has 2 divisors, whose sum is σ = 1211421657602. Its totient is φ = 1211421657600.

The previous prime is 1211421657599. The next prime is 1211421657613. The reversal of 1211421657601 is 1067561241121.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 907159097601 + 304262560000 = 952449^2 + 551600^2 .

It is a cyclic number.

It is not a de Polignac number, because 1211421657601 - 2¹ = 1211421657599 is a prime.

It is a super-3 number, since 3×1211421657601³ (a number of 37 digits) contains 333 as substring.

Together with 1211421657599, it forms a pair of twin primes.

It is not a weakly prime, because it can be changed into another prime (1211421657401) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 605710828800 + 605710828801.

It is an arithmetic number, because the mean of its divisors is an integer number (605710828801).

Almost surely, 2^{1211421657601} is an apocalyptic number.

It is an amenable number.

1211421657601 is a deficient number, since it is larger than the sum of its proper divisors (1).

1211421657601 is an equidigital number, since it uses as much as digits as its factorization.

1211421657601 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 20160, while the sum is 37.

Adding to 1211421657601 its reverse (1067561241121), we get a palindrome (2278982898722).

The spelling of 1211421657601 in words is "one trillion, two hundred eleven billion, four hundred twenty-one million, six hundred fifty-seven thousand, six hundred one".