21139730 has 8 divisors (see below), whose sum is σ = 38051532. Its totient is φ = 8455888.

The previous prime is 21139717. The next prime is 21139747. The reversal of 21139730 is 3793112.

It can be written as a sum of positive squares in 2 ways, for example, as 20097289 + 1042441 = 4483^2 + 1021^2 .

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

It is a self number, because there is not a number n which added to its sum of digits gives 21139730.

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, 1056977 + ... + 1056996.

Almost surely, 2^21139730 is an apocalyptic number.

21139730 is a deficient number, since it is larger than the sum of its proper divisors (16911802).

21139730 is a wasteful number, since it uses less digits than its factorization.

21139730 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2113980.

The product of its (nonzero) digits is 1134, while the sum is 26.

The square root of 21139730 is about 4597.7962112299. The cubic root of 21139730 is about 276.5029773165.

The spelling of 21139730 in words is "twenty-one million, one hundred thirty-nine thousand, seven hundred thirty".