21004707 has 16 divisors (see below), whose sum is σ = 29877120. Its totient is φ = 13080192.

The previous prime is 21004691. The next prime is 21004721. The reversal of 21004707 is 70740012.

It is not a de Polignac number, because 21004707 - 2⁴ = 21004691 is a prime.

It is not an unprimeable number, because it can be changed into a prime (21004807) 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, 5608 + ... + 8570.

It is an arithmetic number, because the mean of its divisors is an integer number (1867320).

Almost surely, 2^21004707 is an apocalyptic number.

21004707 is a deficient number, since it is larger than the sum of its proper divisors (8872413).

21004707 is a wasteful number, since it uses less digits than its factorization.

21004707 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 3122.

The product of its (nonzero) digits is 392, while the sum is 21.

The square root of 21004707 is about 4583.0892419851. The cubic root of 21004707 is about 275.9130292031.

Adding to 21004707 its reverse (70740012), we get a palindrome (91744719).

The spelling of 21004707 in words is "twenty-one million, four thousand, seven hundred seven".