16721340 has 24 divisors (see below), whose sum is σ = 46819920. Its totient is φ = 4459008.

The previous prime is 16721333. The next prime is 16721347. The reversal of 16721340 is 4312761.

It is an interprime number because it is at equal distance from previous prime (16721333) and next prime (16721347).

It is a super-2 number, since 2×16721340² = 559206422791200, which contains 22 as substring.

It is a self number, because there is not a number n which added to its sum of digits gives 16721340.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (16721347) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 139285 + ... + 139404.

It is an arithmetic number, because the mean of its divisors is an integer number (1950830).

Almost surely, 2^16721340 is an apocalyptic number.

16721340 is a gapful number since it is divisible by the number (10) formed by its first and last digit.

It is an amenable number.

16721340 is an abundant number, since it is smaller than the sum of its proper divisors (30098580).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

16721340 is a wasteful number, since it uses less digits than its factorization.

16721340 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 278701 (or 278699 counting only the distinct ones).

The product of its (nonzero) digits is 1008, while the sum is 24.

The square root of 16721340 is about 4089.1735106253. The cubic root of 16721340 is about 255.7154838759.

The spelling of 16721340 in words is "sixteen million, seven hundred twenty-one thousand, three hundred forty".