20421453415406 has 4 divisors (see below), whose sum is σ = 30632180123112. Its totient is φ = 10210726707702.

The previous prime is 20421453415361. The next prime is 20421453415411. The reversal of 20421453415406 is 60451435412402.

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

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, 5105363353850 + ... + 5105363353853.

It is an arithmetic number, because the mean of its divisors is an integer number (7658045030778).

Almost surely, 2^{20421453415406} is an apocalyptic number.

20421453415406 is a deficient number, since it is larger than the sum of its proper divisors (10210726707706).

20421453415406 is a wasteful number, since it uses less digits than its factorization.

20421453415406 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 10210726707705.

The product of its (nonzero) digits is 460800, while the sum is 41.

Adding to 20421453415406 its reverse (60451435412402), we get a palindrome (80872888827808).

The spelling of 20421453415406 in words is "twenty trillion, four hundred twenty-one billion, four hundred fifty-three million, four hundred fifteen thousand, four hundred six".