21012735 has 16 divisors (see below), whose sum is σ = 33707520. Its totient is φ = 11177760.

The previous prime is 21012701. The next prime is 21012737. The reversal of 21012735 is 53721012.

It is not a de Polignac number, because 21012735 - 2⁶ = 21012671 is a prime.

It is a zygodrome in base 4.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21012737) 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, 4990 + ... + 8180.

It is an arithmetic number, because the mean of its divisors is an integer number (2106720).

Almost surely, 2^21012735 is an apocalyptic number.

21012735 is a deficient number, since it is larger than the sum of its proper divisors (12694785).

21012735 is a wasteful number, since it uses less digits than its factorization.

21012735 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 3638.

The product of its (nonzero) digits is 420, while the sum is 21.

The square root of 21012735 is about 4583.9649867773. The cubic root of 21012735 is about 275.9481760500.

Adding to 21012735 its reverse (53721012), we get a palindrome (74733747).

The spelling of 21012735 in words is "twenty-one million, twelve thousand, seven hundred thirty-five".