21554001421 has 8 divisors (see below), whose sum is σ = 22059729824. Its totient is φ = 21048476400.

The previous prime is 21554001401. The next prime is 21554001437. The reversal of 21554001421 is 12410045512.

It is a sphenic number, since it is the product of 3 distinct primes.

It is a cyclic number.

It is not a de Polignac number, because 21554001421 - 2¹¹ = 21553999373 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21554001401) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 175246 + ... + 271696.

It is an arithmetic number, because the mean of its divisors is an integer number (2757466228).

Almost surely, 2^21554001421 is an apocalyptic number.

It is an amenable number.

21554001421 is a deficient number, since it is larger than the sum of its proper divisors (505728403).

21554001421 is an equidigital number, since it uses as much as digits as its factorization.

21554001421 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 101691.

The product of its (nonzero) digits is 1600, while the sum is 25.

Adding to 21554001421 its reverse (12410045512), we get a palindrome (33964046933).

The spelling of 21554001421 in words is "twenty-one billion, five hundred fifty-four million, one thousand, four hundred twenty-one".