20780249961 has 8 divisors (see below), whose sum is σ = 28351348960. Its totient is φ = 13531325472.

The previous prime is 20780249951. The next prime is 20780249969. The reversal of 20780249961 is 16994208702.

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

It is not a de Polignac number, because 20780249961 - 2⁵ = 20780249929 is a prime.

It is a Duffinian number.

It is a self number, because there is not a number n which added to its sum of digits gives 20780249961.

It is not an unprimeable number, because it can be changed into a prime (20780249969) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 80543476 + ... + 80543733.

It is an arithmetic number, because the mean of its divisors is an integer number (3543918620).

Almost surely, 2^20780249961 is an apocalyptic number.

It is an amenable number.

20780249961 is a deficient number, since it is larger than the sum of its proper divisors (7571098999).

20780249961 is a wasteful number, since it uses less digits than its factorization.

20780249961 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 161087255.

The product of its (nonzero) digits is 435456, while the sum is 48.

The spelling of 20780249961 in words is "twenty billion, seven hundred eighty million, two hundred forty-nine thousand, nine hundred sixty-one".