21001320401 has 16 divisors (see below), whose sum is σ = 22288990080. Its totient is φ = 19745320320.

The previous prime is 21001320371. The next prime is 21001320463. The reversal of 21001320401 is 10402310012.

It is a cyclic number.

It is not a de Polignac number, because 21001320401 - 2¹⁸ = 21001058257 is a prime.

It is not an unprimeable number, because it can be changed into a prime (21001320001) 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, 2455190 + ... + 2463728.

It is an arithmetic number, because the mean of its divisors is an integer number (1393061880).

Almost surely, 2^21001320401 is an apocalyptic number.

It is an amenable number.

21001320401 is a deficient number, since it is larger than the sum of its proper divisors (1287669679).

21001320401 is a wasteful number, since it uses less digits than its factorization.

21001320401 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 10376.

The product of its (nonzero) digits is 48, while the sum is 14.

Adding to 21001320401 its reverse (10402310012), we get a palindrome (31403630413).

The spelling of 21001320401 in words is "twenty-one billion, one million, three hundred twenty thousand, four hundred one".