1654181621 has 2 divisors, whose sum is σ = 1654181622. Its totient is φ = 1654181620.

The previous prime is 1654181611. The next prime is 1654181677. The reversal of 1654181621 is 1261814561.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 1639359121 + 14822500 = 40489^2 + 3850^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-1654181621 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (1654181611) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 827090810 + 827090811.

It is an arithmetic number, because the mean of its divisors is an integer number (827090811).

Almost surely, 2^1654181621 is an apocalyptic number.

It is an amenable number.

1654181621 is a deficient number, since it is larger than the sum of its proper divisors (1).

1654181621 is an equidigital number, since it uses as much as digits as its factorization.

1654181621 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 11520, while the sum is 35.

The square root of 1654181621 is about 40671.6316490991. The cubic root of 1654181621 is about 1182.6631464132.

The spelling of 1654181621 in words is "one billion, six hundred fifty-four million, one hundred eighty-one thousand, six hundred twenty-one".