21097270 has 8 divisors (see below), whose sum is σ = 37975104. Its totient is φ = 8438904.

The previous prime is 21097261. The next prime is 21097283. The reversal of 21097270 is 7279012.

It is a happy number.

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

It is a congruent number.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 1054854 + ... + 1054873.

It is an arithmetic number, because the mean of its divisors is an integer number (4746888).

Almost surely, 2^21097270 is an apocalyptic number.

21097270 is a deficient number, since it is larger than the sum of its proper divisors (16877834).

21097270 is a wasteful number, since it uses less digits than its factorization.

21097270 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2109734.

The product of its (nonzero) digits is 1764, while the sum is 28.

The square root of 21097270 is about 4593.1764607949. The cubic root of 21097270 is about 276.3177307768.

The spelling of 21097270 in words is "twenty-one million, ninety-seven thousand, two hundred seventy".