20642558 has 4 divisors (see below), whose sum is σ = 30963840. Its totient is φ = 10321278.

The previous prime is 20642527. The next prime is 20642561. The reversal of 20642558 is 85524602.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 85524602 = 2 ⋅42762301.

It is a super-2 number, since 2×20642558² = 852230401566728, which contains 22 as substring.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 5160638 + ... + 5160641.

It is an arithmetic number, because the mean of its divisors is an integer number (7740960).

Almost surely, 2^20642558 is an apocalyptic number.

20642558 is a deficient number, since it is larger than the sum of its proper divisors (10321282).

20642558 is a wasteful number, since it uses less digits than its factorization.

20642558 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 10321281.

The product of its (nonzero) digits is 19200, while the sum is 32.

The square root of 20642558 is about 4543.4081920954. The cubic root of 20642558 is about 274.3181255361.

The spelling of 20642558 in words is "twenty million, six hundred forty-two thousand, five hundred fifty-eight".