21088381655 has 16 divisors (see below), whose sum is σ = 28018652544. Its totient is φ = 15108091680.

The previous prime is 21088381627. The next prime is 21088381667. The reversal of 21088381655 is 55618388012.

It is a happy number.

It is not a de Polignac number, because 21088381655 - 2⁶ = 21088381591 is a prime.

It is a Duffinian number.

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, 2857697 + ... + 2865066.

It is an arithmetic number, because the mean of its divisors is an integer number (1751165784).

Almost surely, 2^21088381655 is an apocalyptic number.

21088381655 is a deficient number, since it is larger than the sum of its proper divisors (6930270889).

21088381655 is a wasteful number, since it uses less digits than its factorization.

21088381655 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 5722846.

The product of its (nonzero) digits is 460800, while the sum is 47.

The spelling of 21088381655 in words is "twenty-one billion, eighty-eight million, three hundred eighty-one thousand, six hundred fifty-five".