21080890 has 8 divisors (see below), whose sum is σ = 37945620. Its totient is φ = 8432352.

The previous prime is 21080887. The next prime is 21080893. The reversal of 21080890 is 9808012.

It is an interprime number because it is at equal distance from previous prime (21080887) and next prime (21080893).

It can be written as a sum of positive squares in 2 ways, for example, as 17164449 + 3916441 = 4143^2 + 1979^2 .

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

It is not an unprimeable number, because it can be changed into a prime (21080893) 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, 1054035 + ... + 1054054.

Almost surely, 2^21080890 is an apocalyptic number.

21080890 is a deficient number, since it is larger than the sum of its proper divisors (16864730).

21080890 is a wasteful number, since it uses less digits than its factorization.

21080890 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2108096.

The product of its (nonzero) digits is 1152, while the sum is 28.

The square root of 21080890 is about 4591.3930347989. The cubic root of 21080890 is about 276.2462008855.

The spelling of 21080890 in words is "twenty-one million, eighty thousand, eight hundred ninety".