21154961819 has 8 divisors (see below), whose sum is σ = 21556432800. Its totient is φ = 20753576896.

The previous prime is 21154961809. The next prime is 21154961831. The reversal of 21154961819 is 91816945112.

It is a sphenic number, since it is the product of 3 distinct primes.

It is a cyclic number.

It is not a de Polignac number, because 21154961819 - 2⁴ = 21154961803 is a prime.

It is a super-2 number, since 2×21154961819² (a number of 21 digits) contains 22 as substring.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (21154961809) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 704882 + ... + 734280.

It is an arithmetic number, because the mean of its divisors is an integer number (2694554100).

Almost surely, 2^21154961819 is an apocalyptic number.

21154961819 is a deficient number, since it is larger than the sum of its proper divisors (401470981).

21154961819 is a wasteful number, since it uses less digits than its factorization.

21154961819 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 43029.

The product of its digits is 155520, while the sum is 47.

The spelling of 21154961819 in words is "twenty-one billion, one hundred fifty-four million, nine hundred sixty-one thousand, eight hundred nineteen".