20447642 has 4 divisors (see below), whose sum is σ = 30671466. Its totient is φ = 10223820.

The previous prime is 20447587. The next prime is 20447653. The reversal of 20447642 is 24674402.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 24674402 = 2 ⋅12337201.

It can be written as a sum of positive squares in only one way, i.e., 17884441 + 2563201 = 4229^2 + 1601^2 .

It is an unprimeable number.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 5111909 + ... + 5111912.

Almost surely, 2^20447642 is an apocalyptic number.

20447642 is a deficient number, since it is larger than the sum of its proper divisors (10223824).

20447642 is a wasteful number, since it uses less digits than its factorization.

20447642 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 10223823.

The product of its (nonzero) digits is 10752, while the sum is 29.

The square root of 20447642 is about 4521.9068986435. The cubic root of 20447642 is about 273.4519833221.

The spelling of 20447642 in words is "twenty million, four hundred forty-seven thousand, six hundred forty-two".