21000177 has 12 divisors (see below), whose sum is σ = 33091344. Its totient is φ = 12727320.

The previous prime is 21000169. The next prime is 21000191. The reversal of 21000177 is 77100012.

It is not a de Polignac number, because 21000177 - 2³ = 21000169 is a prime.

It is not an unprimeable number, because it can be changed into a prime (21000157) 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 11 ways as a sum of consecutive naturals, for example, 105963 + ... + 106160.

It is an arithmetic number, because the mean of its divisors is an integer number (2757612).

Almost surely, 2^21000177 is an apocalyptic number.

It is an amenable number.

21000177 is a deficient number, since it is larger than the sum of its proper divisors (12091167).

21000177 is a wasteful number, since it uses less digits than its factorization.

21000177 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 212140 (or 212137 counting only the distinct ones).

The product of its (nonzero) digits is 98, while the sum is 18.

The square root of 21000177 is about 4582.5950071984. The cubic root of 21000177 is about 275.8931927623.

Adding to 21000177 its reverse (77100012), we get a palindrome (98100189).

The spelling of 21000177 in words is "twenty-one million, one hundred seventy-seven", and thus it is an aban number.