21740340 has 24 divisors (see below), whose sum is σ = 60873120. Its totient is φ = 5797408.

The previous prime is 21740317. The next prime is 21740347. The reversal of 21740340 is 4304712.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21740347) 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, 181110 + ... + 181229.

It is an arithmetic number, because the mean of its divisors is an integer number (2536380).

Almost surely, 2^21740340 is an apocalyptic number.

21740340 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

21740340 is an abundant number, since it is smaller than the sum of its proper divisors (39132780).

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

21740340 is a wasteful number, since it uses less digits than its factorization.

21740340 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 362351 (or 362349 counting only the distinct ones).

The product of its (nonzero) digits is 672, while the sum is 21.

The square root of 21740340 is about 4662.6537508162. The cubic root of 21740340 is about 279.0971771301.

The spelling of 21740340 in words is "twenty-one million, seven hundred forty thousand, three hundred forty".