21357337 has 4 divisors (see below), whose sum is σ = 21368116. Its totient is φ = 21346560.

The previous prime is 21357331. The next prime is 21357377. The reversal of 21357337 is 73375312.

It is a semiprime because it is the product of two primes, and also a brilliant number, because the two primes have the same length.

It can be written as a sum of positive squares in 2 ways, for example, as 15768841 + 5588496 = 3971^2 + 2364^2 .

It is a cyclic number.

It is not a de Polignac number, because 21357337 - 2¹¹ = 21355289 is a prime.

It is a super-2 number, since 2×21357337² = 912271687463138, which contains 22 as substring.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 21357299 and 21357308.

It is not an unprimeable number, because it can be changed into a prime (21357331) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 1464 + ... + 6697.

It is an arithmetic number, because the mean of its divisors is an integer number (5342029).

Almost surely, 2^21357337 is an apocalyptic number.

It is an amenable number.

21357337 is a deficient number, since it is larger than the sum of its proper divisors (10779).

21357337 is an equidigital number, since it uses as much as digits as its factorization.

21357337 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 10778.

The product of its digits is 13230, while the sum is 31.

The square root of 21357337 is about 4621.3998961354. The cubic root of 21357337 is about 277.4484908318.

The spelling of 21357337 in words is "twenty-one million, three hundred fifty-seven thousand, three hundred thirty-seven".