21021000001 has 8 divisors (see below), whose sum is σ = 21755989800. Its totient is φ = 20286685440.

The previous prime is 21020999981. The next prime is 21021000017. The reversal of 21021000001 is 10000012012.

It can be written as a sum of positive squares in 4 ways, for example, as 10298190400 + 10722809601 = 101480^2 + 103551^2 .

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 21021000001 - 2¹¹ = 21020997953 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (21021000041) 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, 105046 + ... + 230383.

It is an arithmetic number, because the mean of its divisors is an integer number (2719498725).

Almost surely, 2^21021000001 is an apocalyptic number.

It is an amenable number.

21021000001 is a deficient number, since it is larger than the sum of its proper divisors (734989799).

21021000001 is a wasteful number, since it uses less digits than its factorization.

21021000001 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 337619.

The product of its (nonzero) digits is 4, while the sum is 7.

Adding to 21021000001 its reverse (10000012012), we get a palindrome (31021012013).

The spelling of 21021000001 in words is "twenty-one billion, twenty-one million, one", and thus it is an aban number and an uban number.