21231278 has 8 divisors (see below), whose sum is σ = 31877040. Its totient is φ = 10605600.

The previous prime is 21231269. The next prime is 21231307. The reversal of 21231278 is 87213212.

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, 2018 + ... + 6821.

It is an arithmetic number, because the mean of its divisors is an integer number (3984630).

Almost surely, 2^21231278 is an apocalyptic number.

21231278 is a deficient number, since it is larger than the sum of its proper divisors (10645762).

21231278 is a wasteful number, since it uses less digits than its factorization.

21231278 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 10042.

The product of its digits is 1344, while the sum is 26.

The square root of 21231278 is about 4607.7410951571. The cubic root of 21231278 is about 276.9015450297.

The spelling of 21231278 in words is "twenty-one million, two hundred thirty-one thousand, two hundred seventy-eight".