20005661421 has 32 divisors (see below), whose sum is σ = 31390951680. Its totient is φ = 12548763648.

The previous prime is 20005661399. The next prime is 20005661477. The reversal of 20005661421 is 12416650002.

20005661421 is a `hidden beast` number, since 20 + 0 + 0 + 5 + 6 + 614 + 21 = 666.

It is not a de Polignac number, because 20005661421 - 2¹⁵ = 20005628653 is a prime.

It is a Harshad number since it is a multiple of its sum of digits (27).

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (20005661491) by changing a digit.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 2863885 + ... + 2870861.

It is an arithmetic number, because the mean of its divisors is an integer number (980967240).

Almost surely, 2^20005661421 is an apocalyptic number.

It is an amenable number.

20005661421 is a deficient number, since it is larger than the sum of its proper divisors (11385290259).

20005661421 is a wasteful number, since it uses less digits than its factorization.

20005661421 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 13250 (or 13244 counting only the distinct ones).

The product of its (nonzero) digits is 2880, while the sum is 27.

The spelling of 20005661421 in words is "twenty billion, five million, six hundred sixty-one thousand, four hundred twenty-one".