20653978 has 8 divisors (see below), whose sum is σ = 31178772. Its totient is φ = 10261056.

The previous prime is 20653973. The next prime is 20653979. The reversal of 20653978 is 87935602.

It can be written as a sum of positive squares in 2 ways, for example, as 20638849 + 15129 = 4543^2 + 123^2 .

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

It is a self number, because there is not a number n which added to its sum of digits gives 20653978.

It is not an unprimeable number, because it can be changed into a prime (20653973) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 32575 + ... + 33202.

Almost surely, 2^20653978 is an apocalyptic number.

20653978 is a deficient number, since it is larger than the sum of its proper divisors (10524794).

20653978 is a wasteful number, since it uses less digits than its factorization.

20653978 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 65936.

The product of its (nonzero) digits is 90720, while the sum is 40.

The square root of 20653978 is about 4544.6647841177. The cubic root of 20653978 is about 274.3687028510.

The spelling of 20653978 in words is "twenty million, six hundred fifty-three thousand, nine hundred seventy-eight".