351340721820 has 72 divisors (see below), whose sum is σ = 1162618395120. Its totient is φ = 85173507840.

The previous prime is 351340721749. The next prime is 351340721827. The reversal of 351340721820 is 28127043153.

351340721820 is a `hidden beast` number, since 3 + 5 + 13 + 407 + 218 + 20 = 666.

It is a super-2 number, since 2×351340721820² (a number of 24 digits) contains 22 as substring.

It is a Harshad number since it is a multiple of its sum of digits (36).

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (351340721827) by changing a digit.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 88720425 + ... + 88724384.

It is an arithmetic number, because the mean of its divisors is an integer number (16147477710).

Almost surely, 2^351340721820 is an apocalyptic number.

351340721820 is a gapful number since it is divisible by the number (30) formed by its first and last digit.

It is an amenable number.

351340721820 is an abundant number, since it is smaller than the sum of its proper divisors (811277673300).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

351340721820 is a wasteful number, since it uses less digits than its factorization.

351340721820 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 177444835 (or 177444830 counting only the distinct ones).

The product of its (nonzero) digits is 40320, while the sum is 36.

Adding to 351340721820 its reverse (28127043153), we get a palindrome (379467764973).

The spelling of 351340721820 in words is "three hundred fifty-one billion, three hundred forty million, seven hundred twenty-one thousand, eight hundred twenty".