21052051655 has 16 divisors (see below), whose sum is σ = 25530064704. Its totient is φ = 16663468800.

The previous prime is 21052051627. The next prime is 21052051667. The reversal of 21052051655 is 55615025012.

It is not a de Polignac number, because 21052051655 - 2⁶ = 21052051591 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, 765707 + ... + 792723.

It is an arithmetic number, because the mean of its divisors is an integer number (1595629044).

Almost surely, 2^21052051655 is an apocalyptic number.

21052051655 is a deficient number, since it is larger than the sum of its proper divisors (4478013049).

21052051655 is a wasteful number, since it uses less digits than its factorization.

21052051655 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 28666.

The product of its (nonzero) digits is 15000, while the sum is 32.

Adding to 21052051655 its reverse (55615025012), we get a palindrome (76667076667).

The spelling of 21052051655 in words is "twenty-one billion, fifty-two million, fifty-one thousand, six hundred fifty-five".