21054445 has 16 divisors (see below), whose sum is σ = 25920000. Its totient is φ = 16412608.

The previous prime is 21054437. The next prime is 21054457. The reversal of 21054445 is 54445012.

21054445 = 103² + 104² + ... + 400².

It is a happy number.

It is a cyclic number.

It is not a de Polignac number, because 21054445 - 2³ = 21054437 is a prime.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 43716 + ... + 44194.

It is an arithmetic number, because the mean of its divisors is an integer number (1620000).

Almost surely, 2^21054445 is an apocalyptic number.

It is an amenable number.

21054445 is a deficient number, since it is larger than the sum of its proper divisors (4865555).

21054445 is a wasteful number, since it uses less digits than its factorization.

21054445 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 692.

The product of its (nonzero) digits is 3200, while the sum is 25.

The square root of 21054445 is about 4588.5122861337. The cubic root of 21054445 is about 276.1306398624.

Adding to 21054445 its reverse (54445012), we get a palindrome (75499457).

The spelling of 21054445 in words is "twenty-one million, fifty-four thousand, four hundred forty-five".