21423578 has 16 divisors (see below), whose sum is σ = 35294400. Its totient is φ = 9672000.

The previous prime is 21423559. The next prime is 21423581. The reversal of 21423578 is 87532412.

It is an unprimeable number.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 98 + ... + 6546.

It is an arithmetic number, because the mean of its divisors is an integer number (2205900).

Almost surely, 2^21423578 is an apocalyptic number.

21423578 is a deficient number, since it is larger than the sum of its proper divisors (13870822).

21423578 is a wasteful number, since it uses less digits than its factorization.

21423578 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 6613.

The product of its digits is 13440, while the sum is 32.

The square root of 21423578 is about 4628.5611155088. The cubic root of 21423578 is about 277.7350355687.

The spelling of 21423578 in words is "twenty-one million, four hundred twenty-three thousand, five hundred seventy-eight".