20378657 has 4 divisors (see below), whose sum is σ = 21946260. Its totient is φ = 18811056.

The previous prime is 20378647. The next prime is 20378663. The reversal of 20378657 is 75687302.

It is a happy number.

It is a semiprime because it is the product of two primes.

It can be written as a sum of positive squares in 2 ways, for example, as 7447441 + 12931216 = 2729^2 + 3596^2 .

It is a cyclic number.

It is not a de Polignac number, because 20378657 - 2⁶ = 20378593 is a prime.

It is a super-2 number, since 2×20378657² = 830579322247298, which contains 22 as substring.

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 20378657.

It is not an unprimeable number, because it can be changed into a prime (20378647) 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, 783782 + ... + 783807.

It is an arithmetic number, because the mean of its divisors is an integer number (5486565).

Almost surely, 2^20378657 is an apocalyptic number.

It is an amenable number.

20378657 is a deficient number, since it is larger than the sum of its proper divisors (1567603).

20378657 is a wasteful number, since it uses less digits than its factorization.

20378657 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1567602.

The product of its (nonzero) digits is 70560, while the sum is 38.

The square root of 20378657 is about 4514.2725881364. The cubic root of 20378657 is about 273.1441183356.

The spelling of 20378657 in words is "twenty million, three hundred seventy-eight thousand, six hundred fifty-seven".