1621717329 has 16 divisors (see below), whose sum is σ = 2317073472. Its totient is φ = 1005285888.

The previous prime is 1621717297. The next prime is 1621717337. The reversal of 1621717329 is 9237171261.

It is not a de Polignac number, because 1621717329 - 2⁵ = 1621717297 is a prime.

It is not an unprimeable number, because it can be changed into a prime (1621717529) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 187324 + ... + 195789.

It is an arithmetic number, because the mean of its divisors is an integer number (144817092).

Almost surely, 2^1621717329 is an apocalyptic number.

It is an amenable number.

1621717329 is a deficient number, since it is larger than the sum of its proper divisors (695356143).

1621717329 is a wasteful number, since it uses less digits than its factorization.

1621717329 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 383216.

The product of its digits is 31752, while the sum is 39.

The square root of 1621717329 is about 40270.5516351589. The cubic root of 1621717329 is about 1174.8751529340.

It can be divided in two parts, 16 and 21717329, that added together give a triangular number (21717345 = T₆₅₉₀).

The spelling of 1621717329 in words is "one billion, six hundred twenty-one million, seven hundred seventeen thousand, three hundred twenty-nine".