21195981502749 has 24 divisors (see below), whose sum is σ = 31947865065792. Its totient is φ = 13516151668800.

The previous prime is 21195981502687. The next prime is 21195981502771. The reversal of 21195981502749 is 94720518959112.

21195981502749 is a `hidden beast` number, since 2 + 1 + 1 + 9 + 5 + 9 + 81 + 502 + 7 + 49 = 666.

It is not a de Polignac number, because 21195981502749 - 2²⁵ = 21195947948317 is a prime.

It is a Smith number, since the sum of its digits (63) coincides with the sum of the digits of its prime factors.

It is a Curzon number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21195981502349) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (23) of ones.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 24971329 + ... + 25806185.

It is an arithmetic number, because the mean of its divisors is an integer number (1331161044408).

Almost surely, 2^{21195981502749} is an apocalyptic number.

It is an amenable number.

21195981502749 is a deficient number, since it is larger than the sum of its proper divisors (10751883563043).

21195981502749 is a wasteful number, since it uses less digits than its factorization.

21195981502749 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 957537 (or 957534 counting only the distinct ones).

The product of its (nonzero) digits is 16329600, while the sum is 63.

The spelling of 21195981502749 in words is "twenty-one trillion, one hundred ninety-five billion, nine hundred eighty-one million, five hundred two thousand, seven hundred forty-nine".