21390855527 has 4 divisors (see below), whose sum is σ = 21598533840. Its totient is φ = 21183177216.

The previous prime is 21390855511. The next prime is 21390855539. The reversal of 21390855527 is 72555809312.

It is a semiprime because it is the product of two primes.

It is a cyclic number.

It is not a de Polignac number, because 21390855527 - 2⁴ = 21390855511 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21390855127) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (23) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 103839002 + ... + 103839207.

It is an arithmetic number, because the mean of its divisors is an integer number (5399633460).

Almost surely, 2^21390855527 is an apocalyptic number.

21390855527 is a deficient number, since it is larger than the sum of its proper divisors (207678313).

21390855527 is a wasteful number, since it uses less digits than its factorization.

21390855527 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 207678312.

The product of its (nonzero) digits is 756000, while the sum is 47.

The spelling of 21390855527 in words is "twenty-one billion, three hundred ninety million, eight hundred fifty-five thousand, five hundred twenty-seven".