21478793 has 16 divisors (see below), whose sum is σ = 25544064. Its totient is φ = 17677440.

The previous prime is 21478789. The next prime is 21478799. The reversal of 21478793 is 39787412.

It is a cyclic number.

It is not a de Polignac number, because 21478793 - 2² = 21478789 is a prime.

It is a super-2 number, since 2×21478793² = 922677097473698, which contains 22 as substring.

It is a Harshad number since it is a multiple of its sum of digits (41).

It is a Curzon number.

It is a self number, because there is not a number n which added to its sum of digits gives 21478793.

It is not an unprimeable number, because it can be changed into a prime (21478799) 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, 18671 + ... + 19787.

It is an arithmetic number, because the mean of its divisors is an integer number (1596504).

Almost surely, 2^21478793 is an apocalyptic number.

It is an amenable number.

21478793 is a deficient number, since it is larger than the sum of its proper divisors (4065271).

21478793 is a wasteful number, since it uses less digits than its factorization.

21478793 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1232.

The product of its digits is 84672, while the sum is 41.

The square root of 21478793 is about 4634.5218739369. The cubic root of 21478793 is about 277.9734331012.

The spelling of 21478793 in words is "twenty-one million, four hundred seventy-eight thousand, seven hundred ninety-three".