21901629887 has 4 divisors (see below), whose sum is σ = 21933326136. Its totient is φ = 21869933640.

The previous prime is 21901629857. The next prime is 21901629889. The reversal of 21901629887 is 78892610912.

It is a semiprime because it is the product of two primes.

It is a cyclic number.

It is not a de Polignac number, because 21901629887 - 2³⁰ = 20827888063 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 (21901629889) by changing a digit.

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 3 ways as a sum of consecutive naturals, for example, 15847088 + ... + 15848469.

It is an arithmetic number, because the mean of its divisors is an integer number (5483331534).

Almost surely, 2^21901629887 is an apocalyptic number.

21901629887 is a deficient number, since it is larger than the sum of its proper divisors (31696249).

21901629887 is an equidigital number, since it uses as much as digits as its factorization.

21901629887 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 31696248.

The product of its (nonzero) digits is 870912, while the sum is 53.

The spelling of 21901629887 in words is "twenty-one billion, nine hundred one million, six hundred twenty-nine thousand, eight hundred eighty-seven".