21001541405 has 32 divisors (see below), whose sum is σ = 27265910784. Its totient is φ = 15437350656.

The previous prime is 21001541381. The next prime is 21001541441. The reversal of 21001541405 is 50414510012.

It is not a de Polignac number, because 21001541405 - 2¹⁴ = 21001525021 is a prime.

It is a Duffinian number.

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, 19214039 + ... + 19215131.

It is an arithmetic number, because the mean of its divisors is an integer number (852059712).

Almost surely, 2^21001541405 is an apocalyptic number.

It is an amenable number.

21001541405 is a deficient number, since it is larger than the sum of its proper divisors (6264369379).

21001541405 is a wasteful number, since it uses less digits than its factorization.

21001541405 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2205.

The product of its (nonzero) digits is 800, while the sum is 23.

The spelling of 21001541405 in words is "twenty-one billion, one million, five hundred forty-one thousand, four hundred five".