7427973821 has 4 divisors (see below), whose sum is σ = 7441704444. Its totient is φ = 7414243200.

The previous prime is 7427973803. The next prime is 7427973851. The reversal of 7427973821 is 1283797247.

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 4638972100 + 2789001721 = 68110^2 + 52811^2 .

It is a cyclic number.

It is not a de Polignac number, because 7427973821 - 2⁶ = 7427973757 is a prime.

It is a super-2 number, since 2×7427973821² (a number of 21 digits) contains 22 as substring.

It is a Duffinian number.

It is a self number, because there is not a number n which added to its sum of digits gives 7427973821.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (7427973851) 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, 6864500 + ... + 6865581.

It is an arithmetic number, because the mean of its divisors is an integer number (1860426111).

Almost surely, 2^7427973821 is an apocalyptic number.

It is an amenable number.

7427973821 is a deficient number, since it is larger than the sum of its proper divisors (13730623).

7427973821 is a wasteful number, since it uses less digits than its factorization.

7427973821 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 13730622.

The product of its digits is 1185408, while the sum is 50.

The square root of 7427973821 is about 86185.6938302408. The cubic root of 7427973821 is about 1951.1475884529.

The spelling of 7427973821 in words is "seven billion, four hundred twenty-seven million, nine hundred seventy-three thousand, eight hundred twenty-one".