21861274 has 4 divisors (see below), whose sum is σ = 32791914. Its totient is φ = 10930636.

The previous prime is 21861263. The next prime is 21861283. The reversal of 21861274 is 47216812.

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

It can be written as a sum of positive squares in only one way, i.e., 21095649 + 765625 = 4593^2 + 875^2 .

It is a Smith number, since the sum of its digits (31) coincides with the sum of the digits of its prime factors. Since it is squarefree, it is also a hoax number.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 5465317 + ... + 5465320.

Almost surely, 2^21861274 is an apocalyptic number.

21861274 is a deficient number, since it is larger than the sum of its proper divisors (10930640).

21861274 is a wasteful number, since it uses less digits than its factorization.

21861274 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 10930639.

The product of its digits is 5376, while the sum is 31.

The square root of 21861274 is about 4675.6041320882. The cubic root of 21861274 is about 279.6137275692.

The spelling of 21861274 in words is "twenty-one million, eight hundred sixty-one thousand, two hundred seventy-four".