16621139929 has 3 divisors (see below), whose sum is σ = 16621268853. Its totient is φ = 16621011006.

The previous prime is 16621139923. The next prime is 16621139939. The reversal of 16621139929 is 92993112661.

The square root of 16621139929 is 128923.

It is a perfect power (a square), and thus also a powerful number.

It is a semiprime because it is the product of two primes, and also a brilliant number, because the two primes have the same length.

It is not a de Polignac number, because 16621139929 - 2⁵ = 16621139897 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (16621139923) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (23) of ones.

It is a polite number, since it can be written in 2 ways as a sum of consecutive naturals, for example, 64462 + ... + 193384.

It is an arithmetic number, because the mean of its divisors is an integer number (5540422951).

Almost surely, 2^16621139929 is an apocalyptic number.

16621139929 is the 128923-rd square number.

16621139929 is the 64462-nd centered octagonal number.

It is an amenable number.

16621139929 is a deficient number, since it is larger than the sum of its proper divisors (128924).

16621139929 is an frugal number, since it uses more digits than its factorization.

16621139929 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 257846 (or 128923 counting only the distinct ones).

The product of its digits is 314928, while the sum is 49.

Multiplying 16621139929 by its sum of digits (49), we get a square (814435856521 = 902461²).

The spelling of 16621139929 in words is "sixteen billion, six hundred twenty-one million, one hundred thirty-nine thousand, nine hundred twenty-nine".