21316740 has 48 divisors (see below), whose sum is σ = 61750080. Its totient is φ = 5488000.

The previous prime is 21316739. The next prime is 21316741. The reversal of 21316740 is 4761312.

It is an interprime number because it is at equal distance from previous prime (21316739) and next prime (21316741).

It is a self number, because there is not a number n which added to its sum of digits gives 21316740.

It is not an unprimeable number, because it can be changed into a prime (21316741) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 4386 + ... + 7865.

It is an arithmetic number, because the mean of its divisors is an integer number (1286460).

Almost surely, 2^21316740 is an apocalyptic number.

21316740 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

21316740 is an abundant number, since it is smaller than the sum of its proper divisors (40433340).

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

21316740 is a wasteful number, since it uses less digits than its factorization.

21316740 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 12292 (or 12290 counting only the distinct ones).

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

The square root of 21316740 is about 4617.0055230636. The cubic root of 21316740 is about 277.2725837466.

The spelling of 21316740 in words is "twenty-one million, three hundred sixteen thousand, seven hundred forty".