20251847661 has 48 divisors (see below), whose sum is σ = 29338633728. Its totient is φ = 12419114400.

The previous prime is 20251847659. The next prime is 20251847677. The reversal of 20251847661 is 16674815202.

It is a happy number.

It is not a de Polignac number, because 20251847661 - 2¹ = 20251847659 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (20251845661) by changing a digit.

It is a polite number, since it can be written in 47 ways as a sum of consecutive naturals, for example, 5149866 + ... + 5153796.

It is an arithmetic number, because the mean of its divisors is an integer number (611221536).

Almost surely, 2^20251847661 is an apocalyptic number.

It is an amenable number.

20251847661 is a deficient number, since it is larger than the sum of its proper divisors (9086786067).

20251847661 is a wasteful number, since it uses less digits than its factorization.

20251847661 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 4110 (or 4091 counting only the distinct ones).

The product of its (nonzero) digits is 161280, while the sum is 42.

The spelling of 20251847661 in words is "twenty billion, two hundred fifty-one million, eight hundred forty-seven thousand, six hundred sixty-one".