21738855 has 16 divisors (see below), whose sum is σ = 34844544. Its totient is φ = 11573280.

The previous prime is 21738853. The next prime is 21738877. The reversal of 21738855 is 55883712.

It is not a de Polignac number, because 21738855 - 2¹ = 21738853 is a prime.

It is a super-2 number, since 2×21738855² = 945155633422050, which contains 22 as substring.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21738853) 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, 11272 + ... + 13058.

It is an arithmetic number, because the mean of its divisors is an integer number (2177784).

Almost surely, 2^21738855 is an apocalyptic number.

21738855 is a deficient number, since it is larger than the sum of its proper divisors (13105689).

21738855 is a wasteful number, since it uses less digits than its factorization.

21738855 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2606.

The product of its digits is 67200, while the sum is 39.

The square root of 21738855 is about 4662.4945040182. The cubic root of 21738855 is about 279.0908222963.

The spelling of 21738855 in words is "twenty-one million, seven hundred thirty-eight thousand, eight hundred fifty-five".