21097478 has 8 divisors (see below), whose sum is σ = 31812480. Its totient is φ = 10493320.

The previous prime is 21097469. The next prime is 21097481. The reversal of 21097478 is 87479012.

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 polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 27233 + ... + 27996.

It is an arithmetic number, because the mean of its divisors is an integer number (3976560).

Almost surely, 2^21097478 is an apocalyptic number.

21097478 is a deficient number, since it is larger than the sum of its proper divisors (10715002).

21097478 is a wasteful number, since it uses less digits than its factorization.

21097478 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 55422.

The product of its (nonzero) digits is 28224, while the sum is 38.

The square root of 21097478 is about 4593.1991030218. The cubic root of 21097478 is about 276.3186388548.

The spelling of 21097478 in words is "twenty-one million, ninety-seven thousand, four hundred seventy-eight".