21027090 has 32 divisors (see below), whose sum is σ = 57674880. Its totient is φ = 4806144.

The previous prime is 21027077. The next prime is 21027103. The reversal of 21027090 is 9072012.

It is a happy number.

It is an interprime number because it is at equal distance from previous prime (21027077) and next prime (21027103).

It is a Harshad number since it is a multiple of its sum of digits (21).

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, 49855 + ... + 50274.

It is an arithmetic number, because the mean of its divisors is an integer number (1802340).

Almost surely, 2^21027090 is an apocalyptic number.

21027090 is an abundant number, since it is smaller than the sum of its proper divisors (36647790).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

21027090 is a wasteful number, since it uses less digits than its factorization.

21027090 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 100146.

The product of its (nonzero) digits is 252, while the sum is 21.

The square root of 21027090 is about 4585.5305036604. The cubic root of 21027090 is about 276.0110004017.

The spelling of 21027090 in words is "twenty-one million, twenty-seven thousand, ninety".