21257901029 has 4 divisors (see below), whose sum is σ = 21258838560. Its totient is φ = 21256963500.

The previous prime is 21257901011. The next prime is 21257901037. The reversal of 21257901029 is 92010975212.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4.

It is a cyclic number.

It is not a de Polignac number, because 21257901029 - 2²⁰ = 21256852453 is a prime.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 21257900983 and 21257901001.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21257901829) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 433889 + ... + 480390.

It is an arithmetic number, because the mean of its divisors is an integer number (5314709640).

Almost surely, 2^21257901029 is an apocalyptic number.

It is an amenable number.

21257901029 is a deficient number, since it is larger than the sum of its proper divisors (937531).

21257901029 is an equidigital number, since it uses as much as digits as its factorization.

21257901029 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 937530.

The product of its (nonzero) digits is 22680, while the sum is 38.

The spelling of 21257901029 in words is "twenty-one billion, two hundred fifty-seven million, nine hundred one thousand, twenty-nine".