21077707 has 16 divisors (see below), whose sum is σ = 25484800. Its totient is φ = 17076744.

The previous prime is 21077659. The next prime is 21077741. The reversal of 21077707 is 70777012.

It is not a de Polignac number, because 21077707 - 2²³ = 12689099 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (21077747) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 47794 + ... + 48232.

It is an arithmetic number, because the mean of its divisors is an integer number (1592800).

Almost surely, 2^21077707 is an apocalyptic number.

21077707 is a deficient number, since it is larger than the sum of its proper divisors (4407093).

21077707 is an frugal number, since it uses more digits than its factorization.

21077707 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 503 (or 465 counting only the distinct ones).

The product of its (nonzero) digits is 4802, while the sum is 31.

The square root of 21077707 is about 4591.0463948865. The cubic root of 21077707 is about 276.2322967300.

The spelling of 21077707 in words is "twenty-one million, seventy-seven thousand, seven hundred seven".