21389061 has 4 divisors (see below), whose sum is σ = 28518752. Its totient is φ = 14259372.

The previous prime is 21389059. The next prime is 21389063. The reversal of 21389061 is 16098312.

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 an interprime number because it is at equal distance from previous prime (21389059) and next prime (21389063).

It is not a de Polignac number, because 21389061 - 2¹ = 21389059 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21389063) 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, 3564841 + ... + 3564846.

It is an arithmetic number, because the mean of its divisors is an integer number (7129688).

Almost surely, 2^21389061 is an apocalyptic number.

It is an amenable number.

21389061 is a deficient number, since it is larger than the sum of its proper divisors (7129691).

21389061 is an equidigital number, since it uses as much as digits as its factorization.

21389061 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 7129690.

The product of its (nonzero) digits is 2592, while the sum is 30.

The square root of 21389061 is about 4624.8309158282. The cubic root of 21389061 is about 277.5857960506.

The spelling of 21389061 in words is "twenty-one million, three hundred eighty-nine thousand, sixty-one".