21257101102 has 16 divisors (see below), whose sum is σ = 32833874160. Its totient is φ = 10313993088.

The previous prime is 21257101097. The next prime is 21257101153. The reversal of 21257101102 is 20110175212.

It is a super-2 number, since 2×21257101102² (a number of 21 digits) contains 22 as substring.

It is a congruent number.

It is an unprimeable number.

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 7 ways as a sum of consecutive naturals, for example, 350923 + ... + 407014.

It is an arithmetic number, because the mean of its divisors is an integer number (2052117135).

Almost surely, 2^21257101102 is an apocalyptic number.

21257101102 is a deficient number, since it is larger than the sum of its proper divisors (11576773058).

21257101102 is a wasteful number, since it uses less digits than its factorization.

21257101102 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 758355.

The product of its (nonzero) digits is 280, while the sum is 22.

Adding to 21257101102 its reverse (20110175212), we get a palindrome (41367276314).

The spelling of 21257101102 in words is "twenty-one billion, two hundred fifty-seven million, one hundred one thousand, one hundred two".