20506278465 has 32 divisors (see below), whose sum is σ = 36461523840. Its totient is φ = 10934906688.

The previous prime is 20506278461. The next prime is 20506278469. The reversal of 20506278465 is 56487260502.

20506278465 is a `hidden beast` number, since 2 + 0 + 506 + 2 + 7 + 84 + 65 = 666.

It is an interprime number because it is at equal distance from previous prime (20506278461) and next prime (20506278469).

It is not a de Polignac number, because 20506278465 - 2² = 20506278461 is a prime.

It is a Harshad number since it is a multiple of its sum of digits (45).

It is a self number, because there is not a number n which added to its sum of digits gives 20506278465.

It is not an unprimeable number, because it can be changed into a prime (20506278461) by changing a digit.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 1619499 + ... + 1632111.

It is an arithmetic number, because the mean of its divisors is an integer number (1139422620).

Almost surely, 2^20506278465 is an apocalyptic number.

It is an amenable number.

20506278465 is a deficient number, since it is larger than the sum of its proper divisors (15955245375).

20506278465 is a wasteful number, since it uses less digits than its factorization.

20506278465 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 24670 (or 24664 counting only the distinct ones).

The product of its (nonzero) digits is 806400, while the sum is 45.

The spelling of 20506278465 in words is "twenty billion, five hundred six million, two hundred seventy-eight thousand, four hundred sixty-five".