21901292921947 has 2 divisors, whose sum is σ = 21901292921948. Its totient is φ = 21901292921946.

The previous prime is 21901292921929. The next prime is 21901292921971. The reversal of 21901292921947 is 74912929210912.

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 21901292921947 - 2¹¹ = 21901292919899 is a prime.

It is a super-2 number, since 2×21901292921947² (a number of 27 digits) contains 22 as substring.

It is a junction number, because it is equal to n+sod(n) for n = 21901292921891 and 21901292921900.

It is not a weakly prime, because it can be changed into another prime (21901292921047) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10950646460973 + 10950646460974.

It is an arithmetic number, because the mean of its divisors is an integer number (10950646460974).

Almost surely, 2^{21901292921947} is an apocalyptic number.

21901292921947 is a deficient number, since it is larger than the sum of its proper divisors (1).

21901292921947 is an equidigital number, since it uses as much as digits as its factorization.

21901292921947 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 2939328, while the sum is 58.

The spelling of 21901292921947 in words is "twenty-one trillion, nine hundred one billion, two hundred ninety-two million, nine hundred twenty-one thousand, nine hundred forty-seven".