21504401554 has 8 divisors (see below), whose sum is σ = 33128402508. Its totient is φ = 10461600720.

The previous prime is 21504401551. The next prime is 21504401557. The reversal of 21504401554 is 45510440512.

It is a happy number.

It is an interprime number because it is at equal distance from previous prime (21504401551) and next prime (21504401557).

It can be written as a sum of positive squares in 2 ways, for example, as 15132690225 + 6371711329 = 123015^2 + 79823^2 .

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

It is a super-2 number, since 2×21504401554² (a number of 21 digits) contains 22 as substring.

It is not an unprimeable number, because it can be changed into a prime (21504401551) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 145299937 + ... + 145300084.

Almost surely, 2^21504401554 is an apocalyptic number.

21504401554 is a deficient number, since it is larger than the sum of its proper divisors (11624000954).

21504401554 is a wasteful number, since it uses less digits than its factorization.

21504401554 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 290600060.

The product of its (nonzero) digits is 16000, while the sum is 31.

The spelling of 21504401554 in words is "twenty-one billion, five hundred four million, four hundred one thousand, five hundred fifty-four".