10121989 has 4 divisors (see below), whose sum is σ = 10128556. Its totient is φ = 10115424.

The previous prime is 10121963. The next prime is 10121999. The reversal of 10121989 is 98912101.

It is a semiprime because it is the product of two primes, and also a brilliant number, because the two primes have the same length.

It can be written as a sum of positive squares in 2 ways, for example, as 5919489 + 4202500 = 2433^2 + 2050^2 .

It is a cyclic number.

It is not a de Polignac number, because 10121989 - 2¹³ = 10113797 is a prime.

It is a super-2 number, since 2×10121989² = 204909322632242, which contains 22 as substring.

It is a Duffinian number.

It is a self number, because there is not a number n which added to its sum of digits gives 10121989.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (10121939) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 427 + ... + 4519.

It is an arithmetic number, because the mean of its divisors is an integer number (2532139).

Almost surely, 2^10121989 is an apocalyptic number.

It is an amenable number.

10121989 is a deficient number, since it is larger than the sum of its proper divisors (6567).

10121989 is an equidigital number, since it uses as much as digits as its factorization.

10121989 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 6566.

The product of its (nonzero) digits is 1296, while the sum is 31.

The square root of 10121989 is about 3181.5073471548. The cubic root of 10121989 is about 216.3159884152.

The spelling of 10121989 in words is "ten million, one hundred twenty-one thousand, nine hundred eighty-nine".