21262378 has 4 divisors (see below), whose sum is σ = 31893570. Its totient is φ = 10631188.

The previous prime is 21262363. The next prime is 21262399. The reversal of 21262378 is 87326212.

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., 15342889 + 5919489 = 3917^2 + 2433^2 .

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 polite number, since it can be written as a sum of consecutive naturals, namely, 5315593 + ... + 5315596.

Almost surely, 2^21262378 is an apocalyptic number.

21262378 is a deficient number, since it is larger than the sum of its proper divisors (10631192).

21262378 is a wasteful number, since it uses less digits than its factorization.

21262378 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 10631191.

The product of its digits is 8064, while the sum is 31.

The square root of 21262378 is about 4611.1146157952. The cubic root of 21262378 is about 277.0366827047.

The spelling of 21262378 in words is "twenty-one million, two hundred sixty-two thousand, three hundred seventy-eight".