20900402 has 4 divisors (see below), whose sum is σ = 31350606. Its totient is φ = 10450200.

The previous prime is 20900401. The next prime is 20900413. The reversal of 20900402 is 20400902.

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., 16152361 + 4748041 = 4019^2 + 2179^2 .

It is not an unprimeable number, because it can be changed into a prime (20900401) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 5225099 + ... + 5225102.

Almost surely, 2^20900402 is an apocalyptic number.

20900402 is a deficient number, since it is larger than the sum of its proper divisors (10450204).

20900402 is a wasteful number, since it uses less digits than its factorization.

20900402 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 10450203.

The product of its (nonzero) digits is 144, while the sum is 17.

The square root of 20900402 is about 4571.6957466568. The cubic root of 20900402 is about 275.4555622587.

Subtracting from 20900402 its reverse (20400902), we obtain a triangular number (499500 = T₉₉₉).

The spelling of 20900402 in words is "twenty million, nine hundred thousand, four hundred two".