21565150 has 24 divisors (see below), whose sum is σ = 41408064. Its totient is φ = 8347200.

The previous prime is 21565121. The next prime is 21565153. The reversal of 21565150 is 5156512.

21565150 = T₁₁₆₄ + T₁₁₆₅ + ... + T₁₁₉₄.

It is a Harshad number since it is a multiple of its sum of digits (25).

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21565153) by changing a digit.

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 in 11 ways as a sum of consecutive naturals, for example, 5407 + ... + 8506.

It is an arithmetic number, because the mean of its divisors is an integer number (1725336).

Almost surely, 2^21565150 is an apocalyptic number.

21565150 is a deficient number, since it is larger than the sum of its proper divisors (19842914).

21565150 is a wasteful number, since it uses less digits than its factorization.

21565150 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 13956 (or 13951 counting only the distinct ones).

The product of its (nonzero) digits is 1500, while the sum is 25.

The square root of 21565150 is about 4643.8292388933. The cubic root of 21565150 is about 278.3454721978.

The spelling of 21565150 in words is "twenty-one million, five hundred sixty-five thousand, one hundred fifty".