81421624951 has 2 divisors, whose sum is σ = 81421624952. Its totient is φ = 81421624950.

The previous prime is 81421624937. The next prime is 81421624979. The reversal of 81421624951 is 15942612418.

It is a weak prime.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-81421624951 is a prime.

It is a super-2 number, since 2×81421624951² (a number of 23 digits) contains 22 as substring.

It is a junction number, because it is equal to n+sod(n) for n = 81421624898 and 81421624907.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (81421624981) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 40710812475 + 40710812476.

It is an arithmetic number, because the mean of its divisors is an integer number (40710812476).

Almost surely, 2^81421624951 is an apocalyptic number.

81421624951 is a deficient number, since it is larger than the sum of its proper divisors (1).

81421624951 is an equidigital number, since it uses as much as digits as its factorization.

81421624951 is an evil number, because the sum of its binary digits is even.

The product of its digits is 138240, while the sum is 43.

The spelling of 81421624951 in words is "eighty-one billion, four hundred twenty-one million, six hundred twenty-four thousand, nine hundred fifty-one".