21480012749 has 4 divisors (see below), whose sum is σ = 23132321436. Its totient is φ = 19827704064.

The previous prime is 21480012713. The next prime is 21480012769. The reversal of 21480012749 is 94721008412.

It is a happy number.

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

It can be written as a sum of positive squares in 2 ways, for example, as 3792342724 + 17687670025 = 61582^2 + 132995^2 .

It is a cyclic number.

It is not a de Polignac number, because 21480012749 - 2⁸ = 21480012493 is a prime.

It is a super-2 number, since 2×21480012749² (a number of 21 digits) contains 22 as substring.

It is a Duffinian number.

It is a Curzon number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21480012769) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 826154324 + ... + 826154349.

It is an arithmetic number, because the mean of its divisors is an integer number (5783080359).

Almost surely, 2^21480012749 is an apocalyptic number.

It is an amenable number.

21480012749 is a deficient number, since it is larger than the sum of its proper divisors (1652308687).

21480012749 is a wasteful number, since it uses less digits than its factorization.

21480012749 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1652308686.

The product of its (nonzero) digits is 32256, while the sum is 38.

The spelling of 21480012749 in words is "twenty-one billion, four hundred eighty million, twelve thousand, seven hundred forty-nine".