21172050 has 48 divisors (see below), whose sum is σ = 58344480. Its totient is φ = 5645520.

The previous prime is 21172037. The next prime is 21172057. The reversal of 21172050 is 5027112.

It is a Harshad number since it is a multiple of its sum of digits (18).

It is not an unprimeable number, because it can be changed into a prime (21172057) 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 23 ways as a sum of consecutive naturals, for example, 6492 + ... + 9191.

It is an arithmetic number, because the mean of its divisors is an integer number (1215510).

Almost surely, 2^21172050 is an apocalyptic number.

21172050 is an abundant number, since it is smaller than the sum of its proper divisors (37172430).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

21172050 is a wasteful number, since it uses less digits than its factorization.

21172050 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 15704 (or 15693 counting only the distinct ones).

The product of its (nonzero) digits is 140, while the sum is 18.

The square root of 21172050 is about 4601.3095961911. The cubic root of 21172050 is about 276.6438183741.

Adding to 21172050 its reverse (5027112), we get a palindrome (26199162).

The spelling of 21172050 in words is "twenty-one million, one hundred seventy-two thousand, fifty".