21201011001 has 48 divisors (see below), whose sum is σ = 32330188800. Its totient is φ = 13361727456.

The previous prime is 21201010991. The next prime is 21201011003. The reversal of 21201011001 is 10011010212.

It is a happy number.

It is not a de Polignac number, because 21201011001 - 2⁶ = 21201010937 is a prime.

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

It is not an unprimeable number, because it can be changed into a prime (21201011003) by changing a digit.

It is a polite number, since it can be written in 47 ways as a sum of consecutive naturals, for example, 6875206 + ... + 6878288.

It is an arithmetic number, because the mean of its divisors is an integer number (673545600).

Almost surely, 2^21201011001 is an apocalyptic number.

It is an amenable number.

21201011001 is a deficient number, since it is larger than the sum of its proper divisors (11129177799).

21201011001 is a wasteful number, since it uses less digits than its factorization.

21201011001 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 3490 (or 3487 counting only the distinct ones).

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

Adding to 21201011001 its reverse (10011010212), we get a palindrome (31212021213).

The spelling of 21201011001 in words is "twenty-one billion, two hundred one million, eleven thousand, one".