20720402 has 4 divisors (see below), whose sum is σ = 31080606. Its totient is φ = 10360200.

The previous prime is 20720363. The next prime is 20720417. The reversal of 20720402 is 20402702.

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

It can be written as a sum of positive squares in only one way, i.e., 17901361 + 2819041 = 4231^2 + 1679^2 .

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 5180099 + ... + 5180102.

Almost surely, 2^20720402 is an apocalyptic number.

20720402 is a deficient number, since it is larger than the sum of its proper divisors (10360204).

20720402 is a wasteful number, since it uses less digits than its factorization.

20720402 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 10360203.

The product of its (nonzero) digits is 224, while the sum is 17.

The square root of 20720402 is about 4551.9668276471. The cubic root of 20720402 is about 274.6625149271.

The spelling of 20720402 in words is "twenty million, seven hundred twenty thousand, four hundred two".