21097490 has 16 divisors (see below), whose sum is σ = 38346048. Its totient is φ = 8356656.

The previous prime is 21097487. The next prime is 21097513. The reversal of 21097490 is 9479012.

It is an unprimeable number.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 9212 + ... + 11271.

It is an arithmetic number, because the mean of its divisors is an integer number (2396628).

Almost surely, 2^21097490 is an apocalyptic number.

21097490 is a deficient number, since it is larger than the sum of its proper divisors (17248558).

21097490 is a wasteful number, since it uses less digits than its factorization.

21097490 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 20593.

The product of its (nonzero) digits is 4536, while the sum is 32.

The square root of 21097490 is about 4593.2004093007. The cubic root of 21097490 is about 276.3186912437.

The spelling of 21097490 in words is "twenty-one million, ninety-seven thousand, four hundred ninety".