21070707 has 8 divisors (see below), whose sum is σ = 32107776. Its totient is φ = 12040392.

The previous prime is 21070703. The next prime is 21070727. The reversal of 21070707 is 70707012.

It is a sphenic number, since it is the product of 3 distinct primes.

It is not a de Polignac number, because 21070707 - 2² = 21070703 is a prime.

It is an alternating number because its digits alternate between even and odd.

21070707 is a modest number, since divided by 70707 gives 21 as remainder.

It is not an unprimeable number, because it can be changed into a prime (21070703) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 501663 + ... + 501704.

It is an arithmetic number, because the mean of its divisors is an integer number (4013472).

Almost surely, 2^21070707 is an apocalyptic number.

21070707 is a deficient number, since it is larger than the sum of its proper divisors (11037069).

21070707 is a wasteful number, since it uses less digits than its factorization.

21070707 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1003377.

The product of its (nonzero) digits is 686, while the sum is 24.

The square root of 21070707 is about 4590.2839781434. The cubic root of 21070707 is about 276.2017140205.

Adding to 21070707 its reverse (70707012), we get a palindrome (91777719).

The spelling of 21070707 in words is "twenty-one million, seventy thousand, seven hundred seven".