21207001055 has 32 divisors (see below), whose sum is σ = 26095436928. Its totient is φ = 16539955200.

The previous prime is 21207001043. The next prime is 21207001091. The reversal of 21207001055 is 55010070212.

It is a happy number.

It is not a de Polignac number, because 21207001055 - 2¹² = 21206996959 is a prime.

It is a super-2 number, since 2×21207001055² (a number of 21 digits) contains 22 as substring.

It is a self number, because there is not a number n which added to its sum of digits gives 21207001055.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 19331267 + ... + 19332363.

It is an arithmetic number, because the mean of its divisors is an integer number (815482404).

Almost surely, 2^21207001055 is an apocalyptic number.

21207001055 is a deficient number, since it is larger than the sum of its proper divisors (4888435873).

21207001055 is a wasteful number, since it uses less digits than its factorization.

21207001055 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1667.

The product of its (nonzero) digits is 700, while the sum is 23.

Adding to 21207001055 its reverse (55010070212), we get a palindrome (76217071267).

The spelling of 21207001055 in words is "twenty-one billion, two hundred seven million, one thousand, fifty-five".