21140278 has 4 divisors (see below), whose sum is σ = 31710420. Its totient is φ = 10570138.

The previous prime is 21140239. The next prime is 21140291. The reversal of 21140278 is 87204112.

It is a happy number.

It is a semiprime because it is the product of two primes.

It is a super-2 number, since 2×21140278² = 893822707834568, which contains 22 as substring.

It is a congruent number.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 5285068 + ... + 5285071.

It is an arithmetic number, because the mean of its divisors is an integer number (7927605).

Almost surely, 2^21140278 is an apocalyptic number.

21140278 is a deficient number, since it is larger than the sum of its proper divisors (10570142).

21140278 is a wasteful number, since it uses less digits than its factorization.

21140278 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 10570141.

The product of its (nonzero) digits is 896, while the sum is 25.

The square root of 21140278 is about 4597.8558046115. The cubic root of 21140278 is about 276.5053665354.

The spelling of 21140278 in words is "twenty-one million, one hundred forty thousand, two hundred seventy-eight".