16251241621 has 2 divisors, whose sum is σ = 16251241622. Its totient is φ = 16251241620.

The previous prime is 16251241609. The next prime is 16251241637. The reversal of 16251241621 is 12614215261.

It is a happy number.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 16214202225 + 37039396 = 127335^2 + 6086^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-16251241621 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (16251241661) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 8125620810 + 8125620811.

It is an arithmetic number, because the mean of its divisors is an integer number (8125620811).

Almost surely, 2^16251241621 is an apocalyptic number.

It is an amenable number.

16251241621 is a deficient number, since it is larger than the sum of its proper divisors (1).

16251241621 is an equidigital number, since it uses as much as digits as its factorization.

16251241621 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 5760, while the sum is 31.

Adding to 16251241621 its reverse (12614215261), we get a palindrome (28865456882).

The spelling of 16251241621 in words is "sixteen billion, two hundred fifty-one million, two hundred forty-one thousand, six hundred twenty-one".