1225720500 has 48 divisors (see below), whose sum is σ = 3569302464. Its totient is φ = 326858400.

The previous prime is 1225720493. The next prime is 1225720513. The reversal of 1225720500 is 50275221.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 407074 + ... + 410073.

It is an arithmetic number, because the mean of its divisors is an integer number (74360468).

Almost surely, 2^1225720500 is an apocalyptic number.

1225720500 is a gapful number since it is divisible by the number (10) formed by its first and last digit.

It is an amenable number.

1225720500 is an abundant number, since it is smaller than the sum of its proper divisors (2343581964).

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

1225720500 is a wasteful number, since it uses less digits than its factorization.

1225720500 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 817169 (or 817157 counting only the distinct ones).

The product of its (nonzero) digits is 1400, while the sum is 24.

The square root of 1225720500 is about 35010.2913441177. The cubic root of 1225720500 is about 1070.1972152278.

Adding to 1225720500 its reverse (50275221), we get a palindrome (1275995721).

The spelling of 1225720500 in words is "one billion, two hundred twenty-five million, seven hundred twenty thousand, five hundred".