16921407 has 8 divisors (see below), whose sum is σ = 22688640. Its totient is φ = 11217560.

The previous prime is 16921391. The next prime is 16921427. The reversal of 16921407 is 70412961.

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 16921407 - 2⁴ = 16921391 is a prime.

It is a plaindrome in base 14.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (16921427) 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, 15219 + ... + 16292.

It is an arithmetic number, because the mean of its divisors is an integer number (2836080).

Almost surely, 2^16921407 is an apocalyptic number.

16921407 is a deficient number, since it is larger than the sum of its proper divisors (5767233).

16921407 is a wasteful number, since it uses less digits than its factorization.

16921407 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 31693.

The product of its (nonzero) digits is 3024, while the sum is 30.

The square root of 16921407 is about 4113.5637833878. The cubic root of 16921407 is about 256.7313022876.

The spelling of 16921407 in words is "sixteen million, nine hundred twenty-one thousand, four hundred seven".