21316737 has 8 divisors (see below), whose sum is σ = 30608704. Its totient is φ = 13117968.

The previous prime is 21316723. The next prime is 21316739. The reversal of 21316737 is 73761312.

It is a sphenic number, since it is the product of 3 distinct primes.

It is not a de Polignac number, because 21316737 - 2⁴ = 21316721 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (21316739) 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, 273253 + ... + 273330.

It is an arithmetic number, because the mean of its divisors is an integer number (3826088).

Almost surely, 2^21316737 is an apocalyptic number.

It is an amenable number.

21316737 is a deficient number, since it is larger than the sum of its proper divisors (9291967).

21316737 is a wasteful number, since it uses less digits than its factorization.

21316737 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 546599.

The product of its digits is 5292, while the sum is 30.

The square root of 21316737 is about 4617.0051981777. The cubic root of 21316737 is about 277.2725707393.

The spelling of 21316737 in words is "twenty-one million, three hundred sixteen thousand, seven hundred thirty-seven".