21001554452 has 12 divisors (see below), whose sum is σ = 38914645140. Its totient is φ = 9883084416.

The previous prime is 21001554451. The next prime is 21001554467. The reversal of 21001554452 is 25445510012.

It can be written as a sum of positive squares in 2 ways, for example, as 9476243716 + 11525310736 = 97346^2 + 107356^2 .

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21001554451) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 154423127 + ... + 154423262.

It is an arithmetic number, because the mean of its divisors is an integer number (3242887095).

Almost surely, 2^21001554452 is an apocalyptic number.

It is an amenable number.

21001554452 is a deficient number, since it is larger than the sum of its proper divisors (17913090688).

21001554452 is a wasteful number, since it uses less digits than its factorization.

21001554452 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 308846410 (or 308846408 counting only the distinct ones).

The product of its (nonzero) digits is 8000, while the sum is 29.

The spelling of 21001554452 in words is "twenty-one billion, one million, five hundred fifty-four thousand, four hundred fifty-two".