20429890 has 32 divisors (see below), whose sum is σ = 40579056. Its totient is φ = 7357440.

The previous prime is 20429881. The next prime is 20429909. The reversal of 20429890 is 9892402.

20429890 = 345² + 346² + ... + 467².

It can be written as a sum of positive squares in 8 ways, for example, as 152881 + 20277009 = 391^2 + 4503^2 .

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 3414 + ... + 7246.

Almost surely, 2^20429890 is an apocalyptic number.

20429890 is a deficient number, since it is larger than the sum of its proper divisors (20149166).

20429890 is a wasteful number, since it uses less digits than its factorization.

20429890 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 3894.

The product of its (nonzero) digits is 10368, while the sum is 34.

The square root of 20429890 is about 4519.9435837187. The cubic root of 20429890 is about 273.3728262719.

The spelling of 20429890 in words is "twenty million, four hundred twenty-nine thousand, eight hundred ninety".