20151601 has 2 divisors, whose sum is σ = 20151602. Its totient is φ = 20151600.

The previous prime is 20151587. The next prime is 20151617. The reversal of 20151601 is 10615102.

It is a happy number.

It is an a-pointer prime, because the next prime (20151617) can be obtained adding 20151601 to its sum of digits (16).

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 17514225 + 2637376 = 4185^2 + 1624^2 .

It is a cyclic number.

It is not a de Polignac number, because 20151601 - 2¹¹ = 20149553 is a prime.

It is not a weakly prime, because it can be changed into another prime (20151701) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10075800 + 10075801.

It is an arithmetic number, because the mean of its divisors is an integer number (10075801).

Almost surely, 2^20151601 is an apocalyptic number.

20151601 is the 2400-th centered heptagonal number.

It is an amenable number.

20151601 is a deficient number, since it is larger than the sum of its proper divisors (1).

20151601 is an equidigital number, since it uses as much as digits as its factorization.

20151601 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 60, while the sum is 16.

The square root of 20151601 is about 4489.0534637048. The cubic root of 20151601 is about 272.1258833764.

Adding to 20151601 its reverse (10615102), we get a palindrome (30766703).

The spelling of 20151601 in words is "twenty million, one hundred fifty-one thousand, six hundred one".