21256043016455 has 16 divisors (see below), whose sum is σ = 27608786229024. Its totient is φ = 15617091181440.

The previous prime is 21256043016449. The next prime is 21256043016487. The reversal of 21256043016455 is 55461034065212.

It is not a de Polignac number, because 21256043016455 - 2⁶ = 21256043016391 is a prime.

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, 829977161 + ... + 830002770.

It is an arithmetic number, because the mean of its divisors is an integer number (1725549139314).

Almost surely, 2^{21256043016455} is an apocalyptic number.

21256043016455 is a deficient number, since it is larger than the sum of its proper divisors (6352743212569).

21256043016455 is a wasteful number, since it uses less digits than its factorization.

21256043016455 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1659980146.

The product of its (nonzero) digits is 864000, while the sum is 44.

The spelling of 21256043016455 in words is "twenty-one trillion, two hundred fifty-six billion, forty-three million, sixteen thousand, four hundred fifty-five".