20878658 has 4 divisors (see below), whose sum is σ = 31317990. Its totient is φ = 10439328.

The previous prime is 20878631. The next prime is 20878667. The reversal of 20878658 is 85687802.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 85687802 = 2 ⋅42843901.

It can be written as a sum of positive squares in only one way, i.e., 19333609 + 1545049 = 4397^2 + 1243^2 .

It is an unprimeable number.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 5219663 + ... + 5219666.

Almost surely, 2^20878658 is an apocalyptic number.

20878658 is a deficient number, since it is larger than the sum of its proper divisors (10439332).

20878658 is a wasteful number, since it uses less digits than its factorization.

20878658 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 10439331.

The product of its (nonzero) digits is 215040, while the sum is 44.

The square root of 20878658 is about 4569.3170167980. The cubic root of 20878658 is about 275.3600045428.

The spelling of 20878658 in words is "twenty million, eight hundred seventy-eight thousand, six hundred fifty-eight".