21155454004 has 24 divisors (see below), whose sum is σ = 39097154880. Its totient is φ = 9995920704.

The previous prime is 21155453987. The next prime is 21155454013. The reversal of 21155454004 is 40045455112.

It is a happy number.

It is a congruent number.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 1377609 + ... + 1392880.

It is an arithmetic number, because the mean of its divisors is an integer number (1629048120).

Almost surely, 2^21155454004 is an apocalyptic number.

It is an amenable number.

21155454004 is a deficient number, since it is larger than the sum of its proper divisors (17941700876).

21155454004 is a wasteful number, since it uses less digits than its factorization.

21155454004 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2770599 (or 2770597 counting only the distinct ones).

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

The spelling of 21155454004 in words is "twenty-one billion, one hundred fifty-five million, four hundred fifty-four thousand, four".