31100020 has 48 divisors (see below), whose sum is σ = 75091968. Its totient is φ = 10598400.

The previous prime is 31100011. The next prime is 31100023. The reversal of 31100020 is 2000113.

It is a super-2 number, since 2×31100020² = 1934422488000800, which contains 22 as substring.

It is a Harshad number since it is a multiple of its sum of digits (7).

It is a junction number, because it is equal to n+sod(n) for n = 31099976 and 31100012.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (31100023) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 26445 + ... + 27595.

It is an arithmetic number, because the mean of its divisors is an integer number (1564416).

Almost surely, 2^31100020 is an apocalyptic number.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 31100020, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (37545984).

31100020 is an abundant number, since it is smaller than the sum of its proper divisors (43991948).

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

31100020 is a wasteful number, since it uses less digits than its factorization.

31100020 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1360 (or 1358 counting only the distinct ones).

The product of its (nonzero) digits is 6, while the sum is 7.

The square root of 31100020 is about 5576.7391906023. The cubic root of 31100020 is about 314.4755529588.

Adding to 31100020 its reverse (2000113), we get a palindrome (33100133).

The spelling of 31100020 in words is "thirty-one million, one hundred thousand, twenty".