16620251 has 4 divisors (see below), whose sum is σ = 16630104. Its totient is φ = 16610400.

The previous prime is 16620239. The next prime is 16620301. The reversal of 16620251 is 15202661.

It is a semiprime because it is the product of two primes, and also a brilliant number, because the two primes have the same length, and also an emirpimes, since its reverse is a distinct semiprime: 15202661 = 1033 ⋅14717.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-16620251 is a prime.

It is a super-3 number, since 3×16620251³ (a number of 23 digits) contains 333 as substring.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (16620551) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 1685 + ... + 6006.

It is an arithmetic number, because the mean of its divisors is an integer number (4157526).

Almost surely, 2^16620251 is an apocalyptic number.

16620251 is a deficient number, since it is larger than the sum of its proper divisors (9853).

16620251 is an equidigital number, since it uses as much as digits as its factorization.

16620251 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 9852.

The product of its (nonzero) digits is 720, while the sum is 23.

The square root of 16620251 is about 4076.7942062361. The cubic root of 16620251 is about 255.1991319091.

The spelling of 16620251 in words is "sixteen million, six hundred twenty thousand, two hundred fifty-one".