21629977 has 2 divisors, whose sum is σ = 21629978. Its totient is φ = 21629976.

The previous prime is 21629957. The next prime is 21630013. The reversal of 21629977 is 77992612.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 10995856 + 10634121 = 3316^2 + 3261^2 .

It is a cyclic number.

It is not a de Polignac number, because 21629977 - 2⁷ = 21629849 is a prime.

It is not a weakly prime, because it can be changed into another prime (21629947) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10814988 + 10814989.

It is an arithmetic number, because the mean of its divisors is an integer number (10814989).

Almost surely, 2^21629977 is an apocalyptic number.

It is an amenable number.

21629977 is a deficient number, since it is larger than the sum of its proper divisors (1).

21629977 is an equidigital number, since it uses as much as digits as its factorization.

21629977 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 95256, while the sum is 43.

The square root of 21629977 is about 4650.8039090033. The cubic root of 21629977 is about 278.6241046375.

The spelling of 21629977 in words is "twenty-one million, six hundred twenty-nine thousand, nine hundred seventy-seven".