102021221261 has 2 divisors, whose sum is σ = 102021221262. Its totient is φ = 102021221260.

The previous prime is 102021221251. The next prime is 102021221329. The reversal of 102021221261 is 162122120201.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 98388868900 + 3632352361 = 313670^2 + 60269^2 .

It is a cyclic number.

It is not a de Polignac number, because 102021221261 - 2³⁴ = 84841352077 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (102021221251) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 51010610630 + 51010610631.

It is an arithmetic number, because the mean of its divisors is an integer number (51010610631).

Almost surely, 2^102021221261 is an apocalyptic number.

It is an amenable number.

102021221261 is a deficient number, since it is larger than the sum of its proper divisors (1).

102021221261 is an equidigital number, since it uses as much as digits as its factorization.

102021221261 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 192, while the sum is 20.

Adding to 102021221261 its reverse (162122120201), we get a palindrome (264143341462).

The spelling of 102021221261 in words is "one hundred two billion, twenty-one million, two hundred twenty-one thousand, two hundred sixty-one".