21215771115031 has 2 divisors, whose sum is σ = 21215771115032. Its totient is φ = 21215771115030.

The previous prime is 21215771114987. The next prime is 21215771115041. The reversal of 21215771115031 is 13051117751212.

It is a strong prime.

It is a cyclic number.

It is not a de Polignac number, because 21215771115031 - 2¹⁷ = 21215770983959 is a prime.

It is a super-2 number, since 2×21215771115031² (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 (21215771115041) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10607885557515 + 10607885557516.

It is an arithmetic number, because the mean of its divisors is an integer number (10607885557516).

Almost surely, 2^{21215771115031} is an apocalyptic number.

21215771115031 is a deficient number, since it is larger than the sum of its proper divisors (1).

21215771115031 is an equidigital number, since it uses as much as digits as its factorization.

21215771115031 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 14700, while the sum is 37.

Adding to 21215771115031 its reverse (13051117751212), we get a palindrome (34266888866243).

The spelling of 21215771115031 in words is "twenty-one trillion, two hundred fifteen billion, seven hundred seventy-one million, one hundred fifteen thousand, thirty-one".