20111021001 has 12 divisors (see below), whose sum is σ = 29050610628. Its totient is φ = 13406720544.

The previous prime is 20111020957. The next prime is 20111021023. The reversal of 20111021001 is 10012011102.

It is a happy number.

It can be written as a sum of positive squares in 2 ways, for example, as 1156340025 + 18954680976 = 34005^2 + 137676^2 .

It is not a de Polignac number, because 20111021001 - 2¹¹ = 20111018953 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 (20111021401) by changing a digit.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 232891 + ... + 307343.

It is an arithmetic number, because the mean of its divisors is an integer number (2420884219).

Almost surely, 2^20111021001 is an apocalyptic number.

It is an amenable number.

20111021001 is a deficient number, since it is larger than the sum of its proper divisors (8939589627).

20111021001 is a wasteful number, since it uses less digits than its factorization.

20111021001 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 104472 (or 104469 counting only the distinct ones).

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

Adding to 20111021001 its reverse (10012011102), we get a palindrome (30123032103).

It can be divided in two parts, 2011102 and 1001, that multiplied together give a palindrome (2013113102).

The spelling of 20111021001 in words is "twenty billion, one hundred eleven million, twenty-one thousand, one".