17649921421 has 32 divisors (see below), whose sum is σ = 20017041408. Its totient is φ = 15423608640.

The previous prime is 17649921371. The next prime is 17649921437. The reversal of 17649921421 is 12412994671.

It is not a de Polignac number, because 17649921421 - 2⁷ = 17649921293 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (17649921481) by changing a digit.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 17422911 + ... + 17423923.

It is an arithmetic number, because the mean of its divisors is an integer number (625532544).

Almost surely, 2^17649921421 is an apocalyptic number.

17649921421 is a gapful number since it is divisible by the number (11) formed by its first and last digit.

It is an amenable number.

17649921421 is a deficient number, since it is larger than the sum of its proper divisors (2367119987).

17649921421 is a wasteful number, since it uses less digits than its factorization.

17649921421 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1641.

The product of its digits is 217728, while the sum is 46.

The spelling of 17649921421 in words is "seventeen billion, six hundred forty-nine million, nine hundred twenty-one thousand, four hundred twenty-one".