21240035 has 24 divisors (see below), whose sum is σ = 27352080. Its totient is φ = 15813504.

The previous prime is 21240001. The next prime is 21240049. The reversal of 21240035 is 53004212.

It is not a de Polignac number, because 21240035 - 2¹⁴ = 21223651 is a prime.

It is a super-2 number, since 2×21240035² = 902278173602450, which contains 22 as substring.

It is a junction number, because it is equal to n+sod(n) for n = 21239995 and 21240022.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 198452 + ... + 198558.

It is an arithmetic number, because the mean of its divisors is an integer number (1139670).

Almost surely, 2^21240035 is an apocalyptic number.

21240035 is a deficient number, since it is larger than the sum of its proper divisors (6112045).

21240035 is a wasteful number, since it uses less digits than its factorization.

21240035 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 215 (or 178 counting only the distinct ones).

The product of its (nonzero) digits is 240, while the sum is 17.

The square root of 21240035 is about 4608.6912458962. The cubic root of 21240035 is about 276.9396098372.

Adding to 21240035 its reverse (53004212), we get a palindrome (74244247).

The spelling of 21240035 in words is "twenty-one million, two hundred forty thousand, thirty-five".