21278654 has 16 divisors (see below), whose sum is σ = 32510160. Its totient is φ = 10443840.

The previous prime is 21278641. The next prime is 21278659. The reversal of 21278654 is 45687212.

It is a super-2 number, since 2×21278654² = 905562232103432, which contains 22 as substring.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21278659) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 30449 + ... + 31139.

It is an arithmetic number, because the mean of its divisors is an integer number (2031885).

Almost surely, 2^21278654 is an apocalyptic number.

21278654 is a deficient number, since it is larger than the sum of its proper divisors (11231506).

21278654 is a wasteful number, since it uses less digits than its factorization.

21278654 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 955.

The product of its digits is 26880, while the sum is 35.

The square root of 21278654 is about 4612.8791443089. The cubic root of 21278654 is about 277.1073536805.

The spelling of 21278654 in words is "twenty-one million, two hundred seventy-eight thousand, six hundred fifty-four".