21077929 has 2 divisors, whose sum is σ = 21077930. Its totient is φ = 21077928.

The previous prime is 21077899. The next prime is 21077951. The reversal of 21077929 is 92977012.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 15681600 + 5396329 = 3960^2 + 2323^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-21077929 is a prime.

It is not a weakly prime, because it can be changed into another prime (21077129) 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 as a sum of consecutive naturals, namely, 10538964 + 10538965.

It is an arithmetic number, because the mean of its divisors is an integer number (10538965).

Almost surely, 2^21077929 is an apocalyptic number.

It is an amenable number.

21077929 is a deficient number, since it is larger than the sum of its proper divisors (1).

21077929 is an equidigital number, since it uses as much as digits as its factorization.

21077929 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 15876, while the sum is 37.

The square root of 21077929 is about 4591.0705723175. The cubic root of 21077929 is about 276.2332665280.

The spelling of 21077929 in words is "twenty-one million, seventy-seven thousand, nine hundred twenty-nine".