21213031031 has 16 divisors (see below), whose sum is σ = 22769531904. Its totient is φ = 19711115424.

The previous prime is 21213031019. The next prime is 21213031039. The reversal of 21213031031 is 13013031212.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-21213031031 is a prime.

It is a super-2 number, since 2×21213031031² (a number of 21 digits) contains 22 as substring.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21213031039) 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, 527810 + ... + 566576.

It is an arithmetic number, because the mean of its divisors is an integer number (1423095744).

Almost surely, 2^21213031031 is an apocalyptic number.

21213031031 is a deficient number, since it is larger than the sum of its proper divisors (1556500873).

21213031031 is a wasteful number, since it uses less digits than its factorization.

21213031031 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 39470.

The product of its (nonzero) digits is 108, while the sum is 17.

Adding to 21213031031 its reverse (13013031212), we get a palindrome (34226062243).

The spelling of 21213031031 in words is "twenty-one billion, two hundred thirteen million, thirty-one thousand, thirty-one".