21392738 has 8 divisors (see below), whose sum is σ = 32114880. Its totient is φ = 10687780.

The previous prime is 21392729. The next prime is 21392741. The reversal of 21392738 is 83729312.

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

It is a junction number, because it is equal to n+sod(n) for n = 21392698 and 21392707.

It is an unprimeable number.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 518 + ... + 6561.

It is an arithmetic number, because the mean of its divisors is an integer number (4014360).

Almost surely, 2^21392738 is an apocalyptic number.

21392738 is a deficient number, since it is larger than the sum of its proper divisors (10722142).

21392738 is a wasteful number, since it uses less digits than its factorization.

21392738 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 8592.

The product of its digits is 18144, while the sum is 35.

The square root of 21392738 is about 4625.2284267915. The cubic root of 21392738 is about 277.6017017588.

The spelling of 21392738 in words is "twenty-one million, three hundred ninety-two thousand, seven hundred thirty-eight".