21001155706257 has 24 divisors (see below), whose sum is σ = 29280812484000. Its totient is φ = 13387978557888.

The previous prime is 21001155706249. The next prime is 21001155706277. The reversal of 21001155706257 is 75260755110012.

It is not a de Polignac number, because 21001155706257 - 2³ = 21001155706249 is a prime.

It is not an unprimeable number, because it can be changed into a prime (21001155706277) by changing a digit.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 3229869 + ... + 7241157.

It is an arithmetic number, because the mean of its divisors is an integer number (1220033853500).

Almost surely, 2^{21001155706257} is an apocalyptic number.

It is an amenable number.

21001155706257 is a deficient number, since it is larger than the sum of its proper divisors (8279656777743).

21001155706257 is a wasteful number, since it uses less digits than its factorization.

21001155706257 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 4014637 (or 4014614 counting only the distinct ones).

The product of its (nonzero) digits is 147000, while the sum is 42.

The spelling of 21001155706257 in words is "twenty-one trillion, one billion, one hundred fifty-five million, seven hundred six thousand, two hundred fifty-seven".