21565142 has 8 divisors (see below), whose sum is σ = 32535216. Its totient is φ = 10720072.

The previous prime is 21565121. The next prime is 21565153. The reversal of 21565142 is 24156512.

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

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 30818 + ... + 31509.

It is an arithmetic number, because the mean of its divisors is an integer number (4066902).

Almost surely, 2^21565142 is an apocalyptic number.

21565142 is a deficient number, since it is larger than the sum of its proper divisors (10970074).

21565142 is a wasteful number, since it uses less digits than its factorization.

21565142 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 62502.

The product of its digits is 2400, while the sum is 26.

The square root of 21565142 is about 4643.8283775351. The cubic root of 21565142 is about 278.3454377786.

The spelling of 21565142 in words is "twenty-one million, five hundred sixty-five thousand, one hundred forty-two".