21395737 has 8 divisors (see below), whose sum is σ = 23388192. Its totient is φ = 19411200.

The previous prime is 21395723. The next prime is 21395747. The reversal of 21395737 is 73759312.

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

It is a cyclic number.

It is not a de Polignac number, because 21395737 - 2¹⁵ = 21362969 is a prime.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 21395696 and 21395705.

It is not an unprimeable number, because it can be changed into a prime (21395747) 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, 4662 + ... + 8032.

It is an arithmetic number, because the mean of its divisors is an integer number (2923524).

Almost surely, 2^21395737 is an apocalyptic number.

It is an amenable number.

21395737 is a deficient number, since it is larger than the sum of its proper divisors (1992455).

21395737 is a wasteful number, since it uses less digits than its factorization.

21395737 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 3959.

The product of its digits is 39690, while the sum is 37.

The square root of 21395737 is about 4625.5526156342. The cubic root of 21395737 is about 277.6146732728.

The spelling of 21395737 in words is "twenty-one million, three hundred ninety-five thousand, seven hundred thirty-seven".