21312121401 has 12 divisors (see below), whose sum is σ = 31155070128. Its totient is φ = 14036898744.

The previous prime is 21312121367. The next prime is 21312121421. The reversal of 21312121401 is 10412121312.

21312121401 is a `hidden beast` number, since 21 + 31 + 212 + 1 + 401 = 666.

It is not a de Polignac number, because 21312121401 - 2⁹ = 21312120889 is a prime.

It is a super-2 number, since 2×21312121401² (a number of 21 digits) contains 22 as substring.

It is a Curzon number.

It is not an unprimeable number, because it can be changed into a prime (21312121421) 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, 14264395 + ... + 14265888.

It is an arithmetic number, because the mean of its divisors is an integer number (2596255844).

Almost surely, 2^21312121401 is an apocalyptic number.

It is an amenable number.

21312121401 is a deficient number, since it is larger than the sum of its proper divisors (9842948727).

21312121401 is a wasteful number, since it uses less digits than its factorization.

21312121401 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 28530372 (or 28530369 counting only the distinct ones).

The product of its (nonzero) digits is 96, while the sum is 18.

Adding to 21312121401 its reverse (10412121312), we get a palindrome (31724242713).

The spelling of 21312121401 in words is "twenty-one billion, three hundred twelve million, one hundred twenty-one thousand, four hundred one".