21035864 has 8 divisors (see below), whose sum is σ = 39442260. Its totient is φ = 10517928.

The previous prime is 21035797. The next prime is 21035867. The reversal of 21035864 is 46853012.

It is a tau number, because it is divible by the number of its divisors (8).

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21035867) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 1314734 + ... + 1314749.

Almost surely, 2^21035864 is an apocalyptic number.

It is an amenable number.

21035864 is a deficient number, since it is larger than the sum of its proper divisors (18406396).

21035864 is a wasteful number, since it uses less digits than its factorization.

21035864 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2629489 (or 2629485 counting only the distinct ones).

The product of its (nonzero) digits is 5760, while the sum is 29.

The square root of 21035864 is about 4586.4871088885. The cubic root of 21035864 is about 276.0493855477.

Adding to 21035864 its reverse (46853012), we get a palindrome (67888876).

The spelling of 21035864 in words is "twenty-one million, thirty-five thousand, eight hundred sixty-four".