21954644 has 6 divisors (see below), whose sum is σ = 38420634. Its totient is φ = 10977320.

The previous prime is 21954643. The next prime is 21954679. The reversal of 21954644 is 44645912.

It can be written as a sum of positive squares in only one way, i.e., 15132100 + 6822544 = 3890^2 + 2612^2 .

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21954643) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 2744327 + ... + 2744334.

It is an arithmetic number, because the mean of its divisors is an integer number (6403439).

Almost surely, 2^21954644 is an apocalyptic number.

It is an amenable number.

21954644 is a deficient number, since it is larger than the sum of its proper divisors (16465990).

21954644 is a wasteful number, since it uses less digits than its factorization.

21954644 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 5488665 (or 5488663 counting only the distinct ones).

The product of its digits is 34560, while the sum is 35.

The square root of 21954644 is about 4685.5782994205. The cubic root of 21954644 is about 280.0112410453.

The spelling of 21954644 in words is "twenty-one million, nine hundred fifty-four thousand, six hundred forty-four".