21428003757 has 4 divisors (see below), whose sum is σ = 28570671680. Its totient is φ = 14285335836.

The previous prime is 21428003693. The next prime is 21428003759. The reversal of 21428003757 is 75730082412.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4.

It is not a de Polignac number, because 21428003757 - 2⁶ = 21428003693 is a prime.

It is a super-2 number, since 2×21428003757² (a number of 21 digits) contains 22 as substring.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21428003759) 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, 3571333957 + ... + 3571333962.

It is an arithmetic number, because the mean of its divisors is an integer number (7142667920).

Almost surely, 2^21428003757 is an apocalyptic number.

It is an amenable number.

21428003757 is a deficient number, since it is larger than the sum of its proper divisors (7142667923).

21428003757 is an equidigital number, since it uses as much as digits as its factorization.

21428003757 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 7142667922.

The product of its (nonzero) digits is 94080, while the sum is 39.

The spelling of 21428003757 in words is "twenty-one billion, four hundred twenty-eight million, three thousand, seven hundred fifty-seven".