21954945 has 16 divisors (see below), whose sum is σ = 35399232. Its totient is φ = 11618880.

The previous prime is 21954941. The next prime is 21954953. The reversal of 21954945 is 54945912.

It is not a de Polignac number, because 21954945 - 2² = 21954941 is a prime.

It is not an unprimeable number, because it can be changed into a prime (21954941) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 3622 + ... + 7551.

It is an arithmetic number, because the mean of its divisors is an integer number (2212452).

Almost surely, 2^21954945 is an apocalyptic number.

It is an amenable number.

21954945 is a deficient number, since it is larger than the sum of its proper divisors (13444287).

21954945 is a wasteful number, since it uses less digits than its factorization.

21954945 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 11312.

The product of its digits is 64800, while the sum is 39.

The square root of 21954945 is about 4685.6104191450. The cubic root of 21954945 is about 280.0125206986.

It can be divided in two parts, 2195 and 4945, that added together give a triangular number (7140 = T₁₁₉).

The spelling of 21954945 in words is "twenty-one million, nine hundred fifty-four thousand, nine hundred forty-five".