21144155451 has 8 divisors (see below), whose sum is σ = 28414193664. Its totient is φ = 13985110440.

The previous prime is 21144155447. The next prime is 21144155479. The reversal of 21144155451 is 15455144112.

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

It is not a de Polignac number, because 21144155451 - 2² = 21144155447 is a prime.

It is not an unprimeable number, because it can be changed into a prime (21144155401) 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, 27747855 + ... + 27748616.

It is an arithmetic number, because the mean of its divisors is an integer number (3551774208).

Almost surely, 2^21144155451 is an apocalyptic number.

21144155451 is a deficient number, since it is larger than the sum of its proper divisors (7270038213).

21144155451 is a wasteful number, since it uses less digits than its factorization.

21144155451 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 55496601.

The product of its digits is 16000, while the sum is 33.

Adding to 21144155451 its reverse (15455144112), we get a palindrome (36599299563).

The spelling of 21144155451 in words is "twenty-one billion, one hundred forty-four million, one hundred fifty-five thousand, four hundred fifty-one".