21501293161 has 2 divisors, whose sum is σ = 21501293162. Its totient is φ = 21501293160.

The previous prime is 21501293153. The next prime is 21501293189. The reversal of 21501293161 is 16139210512.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 19415635600 + 2085657561 = 139340^2 + 45669^2 .

It is a cyclic number.

It is not a de Polignac number, because 21501293161 - 2³ = 21501293153 is a prime.

It is not a weakly prime, because it can be changed into another prime (21507293161) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10750646580 + 10750646581.

It is an arithmetic number, because the mean of its divisors is an integer number (10750646581).

Almost surely, 2^21501293161 is an apocalyptic number.

It is an amenable number.

21501293161 is a deficient number, since it is larger than the sum of its proper divisors (1).

21501293161 is an equidigital number, since it uses as much as digits as its factorization.

21501293161 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 3240, while the sum is 31.

The spelling of 21501293161 in words is "twenty-one billion, five hundred one million, two hundred ninety-three thousand, one hundred sixty-one".