21307078 has 8 divisors (see below), whose sum is σ = 34419168. Its totient is φ = 9834024.

The previous prime is 21307057. The next prime is 21307081. The reversal of 21307078 is 87070312.

It is a happy number.

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

It is a congruent number.

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, 409726 + ... + 409777.

It is an arithmetic number, because the mean of its divisors is an integer number (4302396).

Almost surely, 2^21307078 is an apocalyptic number.

21307078 is a deficient number, since it is larger than the sum of its proper divisors (13112090).

21307078 is a wasteful number, since it uses less digits than its factorization.

21307078 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 819518.

The product of its (nonzero) digits is 2352, while the sum is 28.

The square root of 21307078 is about 4615.9590552777. The cubic root of 21307078 is about 277.2306853361.

The spelling of 21307078 in words is "twenty-one million, three hundred seven thousand, seventy-eight".