901668221 has 2 divisors, whose sum is σ = 901668222. Its totient is φ = 901668220.

The previous prime is 901668197. The next prime is 901668223. The reversal of 901668221 is 122866109.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 572644900 + 329023321 = 23930^2 + 18139^2 .

It is an emirp because it is prime and its reverse (122866109) is a distict prime.

It is a cyclic number.

It is not a de Polignac number, because 901668221 - 2²⁶ = 834559357 is a prime.

It is a super-2 number, since 2×901668221² = 1626011161522609682, which contains 22 as substring.

It is a Sophie Germain prime.

Together with 901668223, it forms a pair of twin primes.

It is a Chen prime.

It is a Curzon number.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (901668223) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 450834110 + 450834111.

It is an arithmetic number, because the mean of its divisors is an integer number (450834111).

Almost surely, 2^901668221 is an apocalyptic number.

It is an amenable number.

901668221 is a deficient number, since it is larger than the sum of its proper divisors (1).

901668221 is an equidigital number, since it uses as much as digits as its factorization.

901668221 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 10368, while the sum is 35.

The square root of 901668221 is about 30027.7908111802. The cubic root of 901668221 is about 966.0855533222.

The spelling of 901668221 in words is "nine hundred one million, six hundred sixty-eight thousand, two hundred twenty-one".