21755263557 has 16 divisors (see below), whose sum is σ = 29776605440. Its totient is φ = 14123745792.

The previous prime is 21755263531. The next prime is 21755263571. The reversal of 21755263557 is 75536255712.

It is not a de Polignac number, because 21755263557 - 2¹⁵ = 21755230789 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 (21755265557) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 611428 + ... + 646029.

It is an arithmetic number, because the mean of its divisors is an integer number (1861037840).

Almost surely, 2^21755263557 is an apocalyptic number.

It is an amenable number.

21755263557 is a deficient number, since it is larger than the sum of its proper divisors (8021341883).

21755263557 is a wasteful number, since it uses less digits than its factorization.

21755263557 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1257612.

The product of its digits is 2205000, while the sum is 48.

The spelling of 21755263557 in words is "twenty-one billion, seven hundred fifty-five million, two hundred sixty-three thousand, five hundred fifty-seven".