21870398 has 16 divisors (see below), whose sum is σ = 37893744. Its totient is φ = 9356160.

The previous prime is 21870389. The next prime is 21870403. The reversal of 21870398 is 89307812.

It is a congruent number.

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, 28865 + ... + 29612.

It is an arithmetic number, because the mean of its divisors is an integer number (2368359).

Almost surely, 2^21870398 is an apocalyptic number.

21870398 is a deficient number, since it is larger than the sum of its proper divisors (16023346).

21870398 is a wasteful number, since it uses less digits than its factorization.

21870398 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 58507.

The product of its (nonzero) digits is 24192, while the sum is 38.

The square root of 21870398 is about 4676.5797330955. The cubic root of 21870398 is about 279.6526219296.

The spelling of 21870398 in words is "twenty-one million, eight hundred seventy thousand, three hundred ninety-eight".