21755254705 has 16 divisors (see below), whose sum is σ = 27782306640. Its totient is φ = 16297265152.

The previous prime is 21755254663. The next prime is 21755254721. The reversal of 21755254705 is 50745255712.

It can be written as a sum of positive squares in 8 ways, for example, as 1782781729 + 19972472976 = 42223^2 + 141324^2 .

It is not a de Polignac number, because 21755254705 - 2⁹ = 21755254193 is a prime.

It is a super-2 number, since 2×21755254705² (a number of 21 digits) contains 22 as substring.

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, 632860 + ... + 666349.

It is an arithmetic number, because the mean of its divisors is an integer number (1736394165).

Almost surely, 2^21755254705 is an apocalyptic number.

It is an amenable number.

21755254705 is a deficient number, since it is larger than the sum of its proper divisors (6027051935).

21755254705 is a wasteful number, since it uses less digits than its factorization.

21755254705 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1299428.

The product of its (nonzero) digits is 490000, while the sum is 43.

The spelling of 21755254705 in words is "twenty-one billion, seven hundred fifty-five million, two hundred fifty-four thousand, seven hundred five".