21727290 has 32 divisors (see below), whose sum is σ = 56157696. Its totient is φ = 5348160.

The previous prime is 21727289. The next prime is 21727331. The reversal of 21727290 is 9272712.

It is a happy number.

It is a Harshad number since it is a multiple of its sum of digits (30).

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 15 ways as a sum of consecutive naturals, for example, 27466 + ... + 28245.

It is an arithmetic number, because the mean of its divisors is an integer number (1754928).

Almost surely, 2^21727290 is an apocalyptic number.

21727290 is an abundant number, since it is smaller than the sum of its proper divisors (34430406).

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

21727290 is a wasteful number, since it uses less digits than its factorization.

21727290 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 55734.

The product of its (nonzero) digits is 3528, while the sum is 30.

The square root of 21727290 is about 4661.2541230875. The cubic root of 21727290 is about 279.0413217146.

The spelling of 21727290 in words is "twenty-one million, seven hundred twenty-seven thousand, two hundred ninety".