21278053 has 8 divisors (see below), whose sum is σ = 21531608. Its totient is φ = 21026304.

The previous prime is 21278041. The next prime is 21278063. The reversal of 21278053 is 35087212.

It can be written as a sum of positive squares in 4 ways, for example, as 1723969 + 19554084 = 1313^2 + 4422^2 .

It is a sphenic number, since it is the product of 3 distinct primes.

It is a cyclic number.

It is not a de Polignac number, because 21278053 - 2⁵ = 21278021 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21278063) 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, 48925 + ... + 49357.

It is an arithmetic number, because the mean of its divisors is an integer number (2691451).

Almost surely, 2^21278053 is an apocalyptic number.

It is an amenable number.

21278053 is a deficient number, since it is larger than the sum of its proper divisors (253555).

21278053 is a wasteful number, since it uses less digits than its factorization.

21278053 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 903.

The product of its (nonzero) digits is 3360, while the sum is 28.

The square root of 21278053 is about 4612.8140001522. The cubic root of 21278053 is about 277.1047447578.

The spelling of 21278053 in words is "twenty-one million, two hundred seventy-eight thousand, fifty-three".