648220381 has 4 divisors (see below), whose sum is σ = 662012352. Its totient is φ = 634428412.

The previous prime is 648220367. The next prime is 648220403. The reversal of 648220381 is 183022846.

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 648220381 - 2⁷ = 648220253 is a prime.

It is a super-2 number, since 2×648220381² = 840379324687570322, which 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 (648220361) 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, 6895915 + ... + 6896008.

It is an arithmetic number, because the mean of its divisors is an integer number (165503088).

Almost surely, 2^648220381 is an apocalyptic number.

It is an amenable number.

648220381 is a deficient number, since it is larger than the sum of its proper divisors (13791971).

648220381 is a wasteful number, since it uses less digits than its factorization.

648220381 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 13791970.

The product of its (nonzero) digits is 18432, while the sum is 34.

The square root of 648220381 is about 25460.1724463916. The cubic root of 648220381 is about 865.4478311897.

The spelling of 648220381 in words is "six hundred forty-eight million, two hundred twenty thousand, three hundred eighty-one".