21011210001 has 8 divisors (see below), whose sum is σ = 31127718560. Its totient is φ = 14007473316.

The previous prime is 21011209997. The next prime is 21011210023. The reversal of 21011210001 is 10001211012.

It is a happy number.

It is not a de Polignac number, because 21011210001 - 2² = 21011209997 is a prime.

It is a super-2 number, since 2×21011210001² (a number of 21 digits) contains 22 as substring.

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

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (21011210041) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 389096455 + ... + 389096508.

It is an arithmetic number, because the mean of its divisors is an integer number (3890964820).

Almost surely, 2^21011210001 is an apocalyptic number.

It is an amenable number.

21011210001 is a deficient number, since it is larger than the sum of its proper divisors (10116508559).

21011210001 is an equidigital number, since it uses as much as digits as its factorization.

21011210001 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 778192972 (or 778192966 counting only the distinct ones).

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

Adding to 21011210001 its reverse (10001211012), we get a palindrome (31012421013).

The spelling of 21011210001 in words is "twenty-one billion, eleven million, two hundred ten thousand, one".