21111034531 has 2 divisors, whose sum is σ = 21111034532. Its totient is φ = 21111034530.

The previous prime is 21111034481. The next prime is 21111034543. The reversal of 21111034531 is 13543011112.

It is a happy number.

It is a strong prime.

It is a cyclic number.

It is not a de Polignac number, because 21111034531 - 2²³ = 21102645923 is a prime.

It is a super-2 number, since 2×21111034531² (a number of 21 digits) contains 22 as substring.

It is not a weakly prime, because it can be changed into another prime (21111034331) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10555517265 + 10555517266.

It is an arithmetic number, because the mean of its divisors is an integer number (10555517266).

Almost surely, 2^21111034531 is an apocalyptic number.

21111034531 is a deficient number, since it is larger than the sum of its proper divisors (1).

21111034531 is an equidigital number, since it uses as much as digits as its factorization.

21111034531 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 360, while the sum is 22.

Adding to 21111034531 its reverse (13543011112), we get a palindrome (34654045643).

The spelling of 21111034531 in words is "twenty-one billion, one hundred eleven million, thirty-four thousand, five hundred thirty-one".