21090675 has 24 divisors (see below), whose sum is σ = 35087040. Its totient is φ = 11178400.

The previous prime is 21090673. The next prime is 21090677. The reversal of 21090675 is 57609012.

It is an interprime number because it is at equal distance from previous prime (21090673) and next prime (21090677).

It is not a de Polignac number, because 21090675 - 2¹ = 21090673 is a prime.

It is not an unprimeable number, because it can be changed into a prime (21090673) by changing a digit.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 12640 + ... + 14210.

It is an arithmetic number, because the mean of its divisors is an integer number (1461960).

Almost surely, 2^21090675 is an apocalyptic number.

21090675 is a gapful number since it is divisible by the number (25) formed by its first and last digit.

21090675 is a deficient number, since it is larger than the sum of its proper divisors (13996365).

21090675 is a wasteful number, since it uses less digits than its factorization.

21090675 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1763 (or 1758 counting only the distinct ones).

The product of its (nonzero) digits is 3780, while the sum is 30.

The square root of 21090675 is about 4592.4584919191. The cubic root of 21090675 is about 276.2889354974.

Adding to 21090675 its reverse (57609012), we get a palindrome (78699687).

The spelling of 21090675 in words is "twenty-one million, ninety thousand, six hundred seventy-five".