21190645 has 16 divisors (see below), whose sum is σ = 29772288. Its totient is φ = 14175360.

The previous prime is 21190627. The next prime is 21190661. The reversal of 21190645 is 54609112.

It is not a de Polignac number, because 21190645 - 2¹³ = 21182453 is a prime.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 5949 + ... + 8818.

It is an arithmetic number, because the mean of its divisors is an integer number (1860768).

Almost surely, 2^21190645 is an apocalyptic number.

It is an amenable number.

21190645 is a deficient number, since it is larger than the sum of its proper divisors (8581643).

21190645 is a wasteful number, since it uses less digits than its factorization.

21190645 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 14820.

The product of its (nonzero) digits is 2160, while the sum is 28.

The square root of 21190645 is about 4603.3297731099. The cubic root of 21190645 is about 276.7247849711.

Adding to 21190645 its reverse (54609112), we get a palindrome (75799757).

The spelling of 21190645 in words is "twenty-one million, one hundred ninety thousand, six hundred forty-five".