20780631 has 12 divisors (see below), whose sum is σ = 31128552. Its totient is φ = 13853592.

The previous prime is 20780581. The next prime is 20780657. The reversal of 20780631 is 13608702.

20780631 is a `hidden beast` number, since 20 + 7 + 8 + 0 + 631 = 666.

It is not a de Polignac number, because 20780631 - 2⁹ = 20780119 is a prime.

It is a super-2 number, since 2×20780631² = 863669249516322, which contains 22 as substring.

It is a Harshad number since it is a multiple of its sum of digits (27).

It is a junction number, because it is equal to n+sod(n) for n = 20780595 and 20780604.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (20780531) by changing a digit.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 42516 + ... + 43001.

It is an arithmetic number, because the mean of its divisors is an integer number (2594046).

Almost surely, 2^20780631 is an apocalyptic number.

20780631 is a deficient number, since it is larger than the sum of its proper divisors (10347921).

20780631 is an frugal number, since it uses more digits than its factorization.

20780631 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 85532 (or 85520 counting only the distinct ones).

The product of its (nonzero) digits is 2016, while the sum is 27.

The square root of 20780631 is about 4558.5777387251. The cubic root of 20780631 is about 274.9283824524.

The spelling of 20780631 in words is "twenty million, seven hundred eighty thousand, six hundred thirty-one".