21545655 has 16 divisors (see below), whose sum is σ = 35405664. Its totient is φ = 11180160.

The previous prime is 21545653. The next prime is 21545663. The reversal of 21545655 is 55654512.

It is not a de Polignac number, because 21545655 - 2¹ = 21545653 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21545653) 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, 18856 + ... + 19965.

It is an arithmetic number, because the mean of its divisors is an integer number (2212854).

Almost surely, 2^21545655 is an apocalyptic number.

21545655 is a deficient number, since it is larger than the sum of its proper divisors (13860009).

21545655 is a wasteful number, since it uses less digits than its factorization.

21545655 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 38866.

The product of its digits is 30000, while the sum is 33.

The square root of 21545655 is about 4641.7297422405. The cubic root of 21545655 is about 278.2615716924.

The spelling of 21545655 in words is "twenty-one million, five hundred forty-five thousand, six hundred fifty-five".