21011001210 has 64 divisors (see below), whose sum is σ = 56052812160. Its totient is φ = 5600586240.

The previous prime is 21011001197. The next prime is 21011001217. The reversal of 21011001210 is 1210011012.

It is a happy number.

It is a Harshad number since it is a multiple of its sum of digits (9).

It is a junction number, because it is equal to n+sod(n) for n = 21011001192 and 21011001201.

It is not an unprimeable number, because it can be changed into a prime (21011001217) 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, 685105 + ... + 715115.

It is an arithmetic number, because the mean of its divisors is an integer number (875825190).

Almost surely, 2^21011001210 is an apocalyptic number.

21011001210 is an abundant number, since it is smaller than the sum of its proper divisors (35041810950).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

21011001210 is a wasteful number, since it uses less digits than its factorization.

21011001210 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 32620 (or 32614 counting only the distinct ones).

The product of its (nonzero) digits is 4, while the sum is 9.

Adding to 21011001210 its reverse (1210011012), we get a palindrome (22221012222).

The spelling of 21011001210 in words is "twenty-one billion, eleven million, one thousand, two hundred ten".