21212401031 has 4 divisors (see below), whose sum is σ = 21896672064. Its totient is φ = 20528130000.

The previous prime is 21212401003. The next prime is 21212401081. The reversal of 21212401031 is 13010421212.

It is a semiprime because it is the product of two primes.

It is a cyclic number.

It is not a de Polignac number, because 21212401031 - 2⁶ = 21212400967 is a prime.

It is a super-2 number, since 2×21212401031² (a number of 21 digits) contains 22 as substring.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21212401081) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 342135470 + ... + 342135531.

It is an arithmetic number, because the mean of its divisors is an integer number (5474168016).

Almost surely, 2^21212401031 is an apocalyptic number.

21212401031 is a deficient number, since it is larger than the sum of its proper divisors (684271033).

21212401031 is an equidigital number, since it uses as much as digits as its factorization.

21212401031 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 684271032.

The product of its (nonzero) digits is 96, while the sum is 17.

Adding to 21212401031 its reverse (13010421212), we get a palindrome (34222822243).

The spelling of 21212401031 in words is "twenty-one billion, two hundred twelve million, four hundred one thousand, thirty-one".