21206954 has 4 divisors (see below), whose sum is σ = 31810434. Its totient is φ = 10603476.

The previous prime is 21206953. The next prime is 21206971. The reversal of 21206954 is 45960212.

It is a happy number.

It is a semiprime because it is the product of two primes.

It can be written as a sum of positive squares in only one way, i.e., 17098225 + 4108729 = 4135^2 + 2027^2 .

It is not an unprimeable number, because it can be changed into a prime (21206951) 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, 5301737 + ... + 5301740.

Almost surely, 2^21206954 is an apocalyptic number.

21206954 is a deficient number, since it is larger than the sum of its proper divisors (10603480).

21206954 is a wasteful number, since it uses less digits than its factorization.

21206954 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 10603479.

The product of its (nonzero) digits is 4320, while the sum is 29.

The square root of 21206954 is about 4605.1008675164. The cubic root of 21206954 is about 276.7957588561.

The spelling of 21206954 in words is "twenty-one million, two hundred six thousand, nine hundred fifty-four".