16425781 has 2 divisors, whose sum is σ = 16425782. Its totient is φ = 16425780.

The previous prime is 16425763. The next prime is 16425833. The reversal of 16425781 is 18752461.

16425781 is nontrivially palindromic in base 11.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 16329681 + 96100 = 4041^2 + 310^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-16425781 is a prime.

It is a super-2 number, since 2×16425781² = 539612562919922, which contains 22 as substring.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (16425181) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 8212890 + 8212891.

It is an arithmetic number, because the mean of its divisors is an integer number (8212891).

Almost surely, 2^16425781 is an apocalyptic number.

16425781 is the 1813-rd centered decagonal number.

It is an amenable number.

16425781 is a deficient number, since it is larger than the sum of its proper divisors (1).

16425781 is an equidigital number, since it uses as much as digits as its factorization.

16425781 is an evil number, because the sum of its binary digits is even.

The product of its digits is 13440, while the sum is 34.

The square root of 16425781 is about 4052.8731783761. The cubic root of 16425781 is about 254.1998808993.

The spelling of 16425781 in words is "sixteen million, four hundred twenty-five thousand, seven hundred eighty-one".