1016891221 has 2 divisors, whose sum is σ = 1016891222. Its totient is φ = 1016891220.

The previous prime is 1016891207. The next prime is 1016891237. The reversal of 1016891221 is 1221986101.

It is a happy number.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 863478225 + 153412996 = 29385^2 + 12386^2 .

It is a cyclic number.

It is not a de Polignac number, because 1016891221 - 2¹³ = 1016883029 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (1016891021) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 508445610 + 508445611.

It is an arithmetic number, because the mean of its divisors is an integer number (508445611).

Almost surely, 2^1016891221 is an apocalyptic number.

It is an amenable number.

1016891221 is a deficient number, since it is larger than the sum of its proper divisors (1).

1016891221 is an equidigital number, since it uses as much as digits as its factorization.

1016891221 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 1728, while the sum is 31.

The square root of 1016891221 is about 31888.7318813402. The cubic root of 1016891221 is about 1005.5989996951.

The spelling of 1016891221 in words is "one billion, sixteen million, eight hundred ninety-one thousand, two hundred twenty-one".