620431921 has 4 divisors (see below), whose sum is σ = 624895600. Its totient is φ = 615968244.

The previous prime is 620431919. The next prime is 620431927. The reversal of 620431921 is 129134026.

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 a cyclic number.

It is not a de Polignac number, because 620431921 - 2¹ = 620431919 is a prime.

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 620431921.

It is not an unprimeable number, because it can be changed into a prime (620431927) 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, 2231631 + ... + 2231908.

It is an arithmetic number, because the mean of its divisors is an integer number (156223900).

Almost surely, 2^620431921 is an apocalyptic number.

It is an amenable number.

620431921 is a deficient number, since it is larger than the sum of its proper divisors (4463679).

620431921 is a wasteful number, since it uses less digits than its factorization.

620431921 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 4463678.

The product of its (nonzero) digits is 2592, while the sum is 28.

The square root of 620431921 is about 24908.4708683612. The cubic root of 620431921 is about 852.8998630404.

Adding to 620431921 its reverse (129134026), we get a palindrome (749565947).

The spelling of 620431921 in words is "six hundred twenty million, four hundred thirty-one thousand, nine hundred twenty-one".