16621257 has 24 divisors (see below), whose sum is σ = 24805600. Its totient is φ = 9870336.

The previous prime is 16621229. The next prime is 16621259. The reversal of 16621257 is 75212661.

It is not a de Polignac number, because 16621257 - 2⁶ = 16621193 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (16621259) by changing a digit.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 15969 + ... + 16977.

Almost surely, 2^16621257 is an apocalyptic number.

16621257 is a gapful number since it is divisible by the number (17) formed by its first and last digit.

It is an amenable number.

16621257 is a deficient number, since it is larger than the sum of its proper divisors (8184343).

16621257 is a wasteful number, since it uses less digits than its factorization.

16621257 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1065 (or 1048 counting only the distinct ones).

The product of its digits is 5040, while the sum is 30.

The square root of 16621257 is about 4076.9175856277. The cubic root of 16621257 is about 255.2042807512.

It can be divided in two parts, 166212 and 57, that multiplied together give a square (9474084 = 3078²).

The spelling of 16621257 in words is "sixteen million, six hundred twenty-one thousand, two hundred fifty-seven".