16781057 has 8 divisors (see below), whose sum is σ = 17805096. Its totient is φ = 15761152.

The previous prime is 16781033. The next prime is 16781059. The reversal of 16781057 is 75018761.

It can be written as a sum of positive squares in 4 ways, for example, as 2027776 + 14753281 = 1424^2 + 3841^2 .

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 16781057 - 2⁸ = 16780801 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (16781059) 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, 12503 + ... + 13779.

It is an arithmetic number, because the mean of its divisors is an integer number (2225637).

Almost surely, 2^16781057 is an apocalyptic number.

16781057 is a gapful number since it is divisible by the number (17) formed by its first and last digit.

It is an amenable number.

16781057 is a deficient number, since it is larger than the sum of its proper divisors (1024039).

16781057 is a wasteful number, since it uses less digits than its factorization.

16781057 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2067.

The product of its (nonzero) digits is 11760, while the sum is 35.

The square root of 16781057 is about 4096.4688452373. The cubic root of 16781057 is about 256.0195348456.

The spelling of 16781057 in words is "sixteen million, seven hundred eighty-one thousand, fifty-seven".