21554412510 has 64 divisors (see below), whose sum is σ = 54027274752. Its totient is φ = 5493096576.

The previous prime is 21554412491. The next prime is 21554412527. The reversal of 21554412510 is 1521445512.

It is a Harshad number since it is a multiple of its sum of digits (30).

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 805872 + ... + 832188.

It is an arithmetic number, because the mean of its divisors is an integer number (844176168).

Almost surely, 2^21554412510 is an apocalyptic number.

It is a practical number, because each smaller number is the sum of distinct divisors of 21554412510, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (27013637376).

21554412510 is an abundant number, since it is smaller than the sum of its proper divisors (32472862242).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

21554412510 is a wasteful number, since it uses less digits than its factorization.

21554412510 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 27537.

The product of its (nonzero) digits is 8000, while the sum is 30.

The spelling of 21554412510 in words is "twenty-one billion, five hundred fifty-four million, four hundred twelve thousand, five hundred ten".