21154533213031 has 2 divisors, whose sum is σ = 21154533213032. Its totient is φ = 21154533213030.

The previous prime is 21154533213019. The next prime is 21154533213091. The reversal of 21154533213031 is 13031233545112.

It is a weak prime.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-21154533213031 is a prime.

It is a super-2 number, since 2×21154533213031² (a number of 27 digits) contains 22 as substring.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (21154533213091) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10577266606515 + 10577266606516.

It is an arithmetic number, because the mean of its divisors is an integer number (10577266606516).

Almost surely, 2^{21154533213031} is an apocalyptic number.

21154533213031 is a deficient number, since it is larger than the sum of its proper divisors (1).

21154533213031 is an equidigital number, since it uses as much as digits as its factorization.

21154533213031 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 32400, while the sum is 34.

Adding to 21154533213031 its reverse (13031233545112), we get a palindrome (34185766758143).

The spelling of 21154533213031 in words is "twenty-one trillion, one hundred fifty-four billion, five hundred thirty-three million, two hundred thirteen thousand, thirty-one".