21121489 has 4 divisors (see below), whose sum is σ = 21326656. Its totient is φ = 20916324.

The previous prime is 21121453. The next prime is 21121493. The reversal of 21121489 is 98412112.

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.

It is a cyclic number.

It is not a de Polignac number, because 21121489 - 2¹³ = 21113297 is a prime.

It is a super-2 number, since 2×21121489² = 892234595154242, which contains 22 as substring.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (21131489) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 102429 + ... + 102634.

It is an arithmetic number, because the mean of its divisors is an integer number (5331664).

Almost surely, 2^21121489 is an apocalyptic number.

It is an amenable number.

21121489 is a deficient number, since it is larger than the sum of its proper divisors (205167).

21121489 is a wasteful number, since it uses less digits than its factorization.

21121489 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 205166.

The product of its digits is 1152, while the sum is 28.

The square root of 21121489 is about 4595.8121153938. The cubic root of 21121489 is about 276.4234250201.

The spelling of 21121489 in words is "twenty-one million, one hundred twenty-one thousand, four hundred eighty-nine".