21931045 has 8 divisors (see below), whose sum is σ = 26347896. Its totient is φ = 17524416.

The previous prime is 21931033. The next prime is 21931057. The reversal of 21931045 is 54013912.

It is an interprime number because it is at equal distance from previous prime (21931033) and next prime (21931057).

It can be written as a sum of positive squares in 4 ways, for example, as 12159169 + 9771876 = 3487^2 + 3126^2 .

It is a sphenic number, since it is the product of 3 distinct primes.

It is a cyclic number.

It is not a de Polignac number, because 21931045 - 2⁷ = 21930917 is a prime.

It is a Duffinian number.

It is a congruent number.

It is an unprimeable number.

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 7 ways as a sum of consecutive naturals, for example, 3459 + ... + 7471.

It is an arithmetic number, because the mean of its divisors is an integer number (3293487).

Almost surely, 2^21931045 is an apocalyptic number.

It is an amenable number.

21931045 is a deficient number, since it is larger than the sum of its proper divisors (4416851).

21931045 is a wasteful number, since it uses less digits than its factorization.

21931045 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 5111.

The product of its (nonzero) digits is 1080, while the sum is 25.

The square root of 21931045 is about 4683.0593632795. The cubic root of 21931045 is about 279.9108772479.

Adding to 21931045 its reverse (54013912), we get a palindrome (75944957).

The spelling of 21931045 in words is "twenty-one million, nine hundred thirty-one thousand, forty-five".