16625681 has 2 divisors, whose sum is σ = 16625682. Its totient is φ = 16625680.

The previous prime is 16625663. The next prime is 16625689. The reversal of 16625681 is 18652661.

It is a happy number.

16625681 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 16000000 + 625681 = 4000^2 + 791^2 .

It is a cyclic number.

It is not a de Polignac number, because 16625681 - 2¹⁴ = 16609297 is a prime.

It is a super-2 number, since 2×16625681² = 552826537427522, which contains 22 as substring.

It is a Chen prime.

It is not a weakly prime, because it can be changed into another prime (16625689) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 8312840 + 8312841.

It is an arithmetic number, because the mean of its divisors is an integer number (8312841).

Almost surely, 2^16625681 is an apocalyptic number.

It is an amenable number.

16625681 is a deficient number, since it is larger than the sum of its proper divisors (1).

16625681 is an equidigital number, since it uses as much as digits as its factorization.

16625681 is an evil number, because the sum of its binary digits is even.

The product of its digits is 17280, while the sum is 35.

The square root of 16625681 is about 4077.4601162979. The cubic root of 16625681 is about 255.2269209078.

It can be divided in two parts, 16 and 625681, that multiplied together give a square (10010896 = 3164²).

The spelling of 16625681 in words is "sixteen million, six hundred twenty-five thousand, six hundred eighty-one".