16721642 has 24 divisors (see below), whose sum is σ = 30896964. Its totient is φ = 6744192.

The previous prime is 16721641. The next prime is 16721647. The reversal of 16721642 is 24612761.

It can be written as a sum of positive squares in 2 ways, for example, as 16654561 + 67081 = 4081^2 + 259^2 .

It is a super-2 number, since 2×16721642² = 559226622352328, which contains 22 as substring.

It is not an unprimeable number, because it can be changed into a prime (16721641) by changing a digit.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 3353 + ... + 6684.

Almost surely, 2^16721642 is an apocalyptic number.

16721642 is a deficient number, since it is larger than the sum of its proper divisors (14175322).

16721642 is a wasteful number, since it uses less digits than its factorization.

16721642 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 10070 (or 10063 counting only the distinct ones).

The product of its digits is 4032, while the sum is 29.

The square root of 16721642 is about 4089.2104372360. The cubic root of 16721642 is about 255.7170233381.

The spelling of 16721642 in words is "sixteen million, seven hundred twenty-one thousand, six hundred forty-two".