1021101661 has 2 divisors, whose sum is σ = 1021101662. Its totient is φ = 1021101660.

The previous prime is 1021101659. The next prime is 1021101671. The reversal of 1021101661 is 1661011201.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 1019588761 + 1512900 = 31931^2 + 1230^2 .

It is a cyclic number.

It is not a de Polignac number, because 1021101661 - 2¹ = 1021101659 is a prime.

Together with 1021101659, it forms a pair of twin primes.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (1021101671) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 510550830 + 510550831.

It is an arithmetic number, because the mean of its divisors is an integer number (510550831).

Almost surely, 2^1021101661 is an apocalyptic number.

It is an amenable number.

1021101661 is a deficient number, since it is larger than the sum of its proper divisors (1).

1021101661 is an equidigital number, since it uses as much as digits as its factorization.

1021101661 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 72, while the sum is 19.

The square root of 1021101661 is about 31954.6813628301. The cubic root of 1021101661 is about 1006.9849834077.

Adding to 1021101661 its reverse (1661011201), we get a palindrome (2682112862).

The spelling of 1021101661 in words is "one billion, twenty-one million, one hundred one thousand, six hundred sixty-one".