21287035 has 16 divisors (see below), whose sum is σ = 31848192. Its totient is φ = 13269600.

The previous prime is 21287033. The next prime is 21287041. The reversal of 21287035 is 53078212.

It is not a de Polignac number, because 21287035 - 2¹ = 21287033 is a prime.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 21286994 and 21287012.

It is not an unprimeable number, because it can be changed into a prime (21287033) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 27261 + ... + 28030.

It is an arithmetic number, because the mean of its divisors is an integer number (1990512).

Almost surely, 2^21287035 is an apocalyptic number.

21287035 is a deficient number, since it is larger than the sum of its proper divisors (10561157).

21287035 is a wasteful number, since it uses less digits than its factorization.

21287035 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 55314.

The product of its (nonzero) digits is 3360, while the sum is 28.

The square root of 21287035 is about 4613.7874896878. The cubic root of 21287035 is about 277.1437302277.

The spelling of 21287035 in words is "twenty-one million, two hundred eighty-seven thousand, thirty-five".