1016921989 has 4 divisors (see below), whose sum is σ = 1019238880. Its totient is φ = 1014605100.

The previous prime is 1016921959. The next prime is 1016921993. The reversal of 1016921989 is 9891296101.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4, and also an emirpimes, since its reverse is a distinct semiprime: 9891296101 = 2903 ⋅3407267.

It is a cyclic number.

It is not a de Polignac number, because 1016921989 - 2⁵ = 1016921957 is a prime.

It is a super-2 number, since 2×1016921989² = 2068260663423432242, which contains 22 as substring.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (1016921959) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 1157787 + ... + 1158664.

It is an arithmetic number, because the mean of its divisors is an integer number (254809720).

Almost surely, 2^1016921989 is an apocalyptic number.

It is an amenable number.

1016921989 is a deficient number, since it is larger than the sum of its proper divisors (2316891).

1016921989 is an equidigital number, since it uses as much as digits as its factorization.

1016921989 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2316890.

The product of its (nonzero) digits is 69984, while the sum is 46.

The square root of 1016921989 is about 31889.2143051534. The cubic root of 1016921989 is about 1005.6091417035.

The spelling of 1016921989 in words is "one billion, sixteen million, nine hundred twenty-one thousand, nine hundred eighty-nine".