1020120400 has 60 divisors (see below), whose sum is σ = 2639378812. Its totient is φ = 376657920.

The previous prime is 1020120397. The next prime is 1020120401. The reversal of 1020120400 is 40210201.

It can be written as a sum of positive squares in 6 ways, for example, as 350138944 + 669981456 = 18712^2 + 25884^2 .

It is a Harshad number since it is a multiple of its sum of digits (10).

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (1020120401) by changing a digit.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 92889 + ... + 103288.

Almost surely, 2^1020120400 is an apocalyptic number.

1020120400 is a gapful number since it is divisible by the number (10) formed by its first and last digit.

It is an amenable number.

1020120400 is an abundant number, since it is smaller than the sum of its proper divisors (1619258412).

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

1020120400 is a wasteful number, since it uses less digits than its factorization.

1020120400 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 196208 (or 196197 counting only the distinct ones).

The product of its (nonzero) digits is 16, while the sum is 10.

The square root of 1020120400 is about 31939.3237248380. The cubic root of 1020120400 is about 1006.6623149869.

Adding to 1020120400 its reverse (40210201), we get a palindrome (1060330601).

The spelling of 1020120400 in words is "one billion, twenty million, one hundred twenty thousand, four hundred".