21011002001 has 8 divisors (see below), whose sum is σ = 22947239424. Its totient is φ = 19079122320.

The previous prime is 21011001989. The next prime is 21011002031. The reversal of 21011002001 is 10020011012.

It is a sphenic number, since it is the product of 3 distinct primes.

It is a cyclic number.

It is not a de Polignac number, because 21011002001 - 2⁶ = 21011001937 is a prime.

It is a Duffinian number.

It is a self number, because there is not a number n which added to its sum of digits gives 21011002001.

It is not an unprimeable number, because it can be changed into a prime (21011002031) 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, 1079345 + ... + 1098638.

It is an arithmetic number, because the mean of its divisors is an integer number (2868404928).

Almost surely, 2^21011002001 is an apocalyptic number.

It is an amenable number.

21011002001 is a deficient number, since it is larger than the sum of its proper divisors (1936237423).

21011002001 is a wasteful number, since it uses less digits than its factorization.

21011002001 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2178871.

The product of its (nonzero) digits is 4, while the sum is 8.

Adding to 21011002001 its reverse (10020011012), we get a palindrome (31031013013).

The spelling of 21011002001 in words is "twenty-one billion, eleven million, two thousand, one".