21256042163446 has 64 divisors (see below), whose sum is σ = 34870656522240. Its totient is φ = 9680536800000.

The previous prime is 21256042163441. The next prime is 21256042163471. The reversal of 21256042163446 is 64436124065212.

It is a junction number, because it is equal to n+sod(n) for n = 21256042163396 and 21256042163405.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21256042163441) by changing a digit.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 117293626 + ... + 117474706.

It is an arithmetic number, because the mean of its divisors is an integer number (544854008160).

Almost surely, 2^{21256042163446} is an apocalyptic number.

21256042163446 is a deficient number, since it is larger than the sum of its proper divisors (13614614358794).

21256042163446 is a wasteful number, since it uses less digits than its factorization.

21256042163446 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 181781.

The product of its (nonzero) digits is 1658880, while the sum is 46.

The spelling of 21256042163446 in words is "twenty-one trillion, two hundred fifty-six billion, forty-two million, one hundred sixty-three thousand, four hundred forty-six".