25661511601989 has 8 divisors (see below), whose sum is σ = 34215724405632. Its totient is φ = 17107486599840.

The previous prime is 25661511601981. The next prime is 25661511602011. The reversal of 25661511601989 is 98910611516652.

It is a happy number.

It is a sphenic number, since it is the product of 3 distinct primes.

It is not a de Polignac number, because 25661511601989 - 2³ = 25661511601981 is a prime.

It is a super-2 number, since 2×25661511601989² (a number of 28 digits) contains 22 as substring.

It is a Curzon number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (25661511601981) 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, 46631232 + ... + 47178329.

It is an arithmetic number, because the mean of its divisors is an integer number (4276965550704).

Almost surely, 2^{25661511601989} is an apocalyptic number.

It is an amenable number.

25661511601989 is a deficient number, since it is larger than the sum of its proper divisors (8554212803643).

25661511601989 is an equidigital number, since it uses as much as digits as its factorization.

25661511601989 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 93900747.

The product of its (nonzero) digits is 6998400, while the sum is 60.

The spelling of 25661511601989 in words is "twenty-five trillion, six hundred sixty-one billion, five hundred eleven million, six hundred one thousand, nine hundred eighty-nine".