21870007 has 8 divisors (see below), whose sum is σ = 24375600. Its totient is φ = 19499904.

The previous prime is 21869999. The next prime is 21870011. The reversal of 21870007 is 70007812.

It is a happy number.

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 21870007 - 2³ = 21869999 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21870047) 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, 33532 + ... + 34177.

It is an arithmetic number, because the mean of its divisors is an integer number (3046950).

Almost surely, 2^21870007 is an apocalyptic number.

21870007 is a deficient number, since it is larger than the sum of its proper divisors (2505593).

21870007 is a wasteful number, since it uses less digits than its factorization.

21870007 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 67745.

The product of its (nonzero) digits is 784, while the sum is 25.

The square root of 21870007 is about 4676.5379288529. The cubic root of 21870007 is about 279.6509553721.

Adding to 21870007 its reverse (70007812), we get a palindrome (91877819).

It can be divided in two parts, 218 and 70007, that added together give a square (70225 = 265²).

The spelling of 21870007 in words is "twenty-one million, eight hundred seventy thousand, seven".