20401010021 has 16 divisors (see below), whose sum is σ = 25212197376.
Its totient is φ = 16107783936.
The previous prime is 20401010009. The next prime is 20401010059. The reversal of 20401010021 is 12001010402.
Adding to 20401010021 its reverse (12001010402), we get a palindrome (32402020423).
It is a cyclic number.
It is not a de Polignac number, because 20401010021 - 214 = 20400993637 is a prime.
It is a Duffinian number.
It is a Curzon number.
It is a junction number, because it is equal to n+sod(n) for n = 20401009984 and 20401010011.
It is a congruent number.
It is not an unprimeable number, because it can be changed into a prime (20401010821) by changing a digit.
It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 1818206 + ... + 1829391.
It is an arithmetic number, because the mean of its divisors is an integer number (1575762336).
Almost surely, 220401010021 is an apocalyptic number.
It is an amenable number.
20401010021 is a deficient number, since it is larger than the sum of its proper divisors (4811187355).
20401010021 is a wasteful number, since it uses less digits than its factorization.
20401010021 is an evil number, because the sum of its binary digits is even.
The sum of its prime factors is 3647668.
The product of its (nonzero) digits is 16, while the sum is 11.
The spelling of 20401010021 in words is "twenty billion, four hundred one million, ten thousand, twenty-one".