21870407 has 8 divisors (see below), whose sum is σ = 24312960. Its totient is φ = 19536480.

The previous prime is 21870403. The next prime is 21870413. The reversal of 21870407 is 70407812.

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 21870407 - 2² = 21870403 is a prime.

It is a Duffinian number.

It is a self number, because there is not a number n which added to its sum of digits gives 21870407.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21870403) 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, 26732 + ... + 27537.

It is an arithmetic number, because the mean of its divisors is an integer number (3039120).

Almost surely, 2^21870407 is an apocalyptic number.

21870407 is a deficient number, since it is larger than the sum of its proper divisors (2442553).

21870407 is a wasteful number, since it uses less digits than its factorization.

21870407 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 54313.

The product of its (nonzero) digits is 3136, while the sum is 29.

The square root of 21870407 is about 4676.5806953371. The cubic root of 21870407 is about 279.6526602900.

The spelling of 21870407 in words is "twenty-one million, eight hundred seventy thousand, four hundred seven".