21772389 has 4 divisors (see below), whose sum is σ = 29029856. Its totient is φ = 14514924.

The previous prime is 21772381. The next prime is 21772433. The reversal of 21772389 is 98327712.

21772389 is nontrivially palindromic in base 2.

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 not a de Polignac number, because 21772389 - 2³ = 21772381 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 (21772381) 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, 3628729 + ... + 3628734.

It is an arithmetic number, because the mean of its divisors is an integer number (7257464).

Almost surely, 2^21772389 is an apocalyptic number.

It is an amenable number.

21772389 is a deficient number, since it is larger than the sum of its proper divisors (7257467).

21772389 is an equidigital number, since it uses as much as digits as its factorization.

21772389 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 7257466.

The product of its digits is 42336, while the sum is 39.

The square root of 21772389 is about 4666.0892618980. The cubic root of 21772389 is about 279.2342555389.

The spelling of 21772389 in words is "twenty-one million, seven hundred seventy-two thousand, three hundred eighty-nine".