1021156620 has 48 divisors (see below), whose sum is σ = 3119171328. Its totient is φ = 247552960.

The previous prime is 1021156589. The next prime is 1021156621. The reversal of 1021156620 is 266511201.

It is not an unprimeable number, because it can be changed into a prime (1021156621) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 772944 + ... + 774263.

It is an arithmetic number, because the mean of its divisors is an integer number (64982736).

Almost surely, 2^1021156620 is an apocalyptic number.

1021156620 is a gapful number since it is divisible by the number (10) formed by its first and last digit.

It is an amenable number.

1021156620 is an abundant number, since it is smaller than the sum of its proper divisors (2098014708).

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

1021156620 is a wasteful number, since it uses less digits than its factorization.

1021156620 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1547230 (or 1547228 counting only the distinct ones).

The product of its (nonzero) digits is 720, while the sum is 24.

The square root of 1021156620 is about 31955.5413035048. The cubic root of 1021156620 is about 1007.0030494818.

Adding to 1021156620 its reverse (266511201), we get a palindrome (1287667821).

It can be divided in two parts, 1021 and 156620, that added together give a triangular number (157641 = T₅₆₁).

The spelling of 1021156620 in words is "one billion, twenty-one million, one hundred fifty-six thousand, six hundred twenty".