21019954 has 12 divisors (see below), whose sum is σ = 32657274. Its totient is φ = 10146752.

The previous prime is 21019937. The next prime is 21019961. The reversal of 21019954 is 45991012.

It can be written as a sum of positive squares in 3 ways, for example, as 18533025 + 2486929 = 4305^2 + 1577^2 .

It is a congruent number.

It is an unprimeable number.

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 5 ways as a sum of consecutive naturals, for example, 4567 + ... + 7930.

Almost surely, 2^21019954 is an apocalyptic number.

21019954 is a deficient number, since it is larger than the sum of its proper divisors (11637320).

21019954 is a wasteful number, since it uses less digits than its factorization.

21019954 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 12557 (or 12528 counting only the distinct ones).

The product of its (nonzero) digits is 3240, while the sum is 31.

The square root of 21019954 is about 4584.7523379131. The cubic root of 21019954 is about 275.9797734250.

It can be divided in two parts, 210 and 19954, that added together give a square (20164 = 142²).

The spelling of 21019954 in words is "twenty-one million, nineteen thousand, nine hundred fifty-four".