1945397721620 has 24 divisors (see below), whose sum is σ = 4112390421888. Its totient is φ = 773005716000.

The previous prime is 1945397721599. The next prime is 1945397721629. The reversal of 1945397721620 is 261277935491.

It is a happy number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (1945397721629) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 322082696 + ... + 322088735.

It is an arithmetic number, because the mean of its divisors is an integer number (171349600912).

Almost surely, 2^{1945397721620} is an apocalyptic number.

1945397721620 is a gapful number since it is divisible by the number (10) formed by its first and last digit.

It is an amenable number.

1945397721620 is an abundant number, since it is smaller than the sum of its proper divisors (2166992700268).

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

1945397721620 is a wasteful number, since it uses less digits than its factorization.

1945397721620 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 644171591 (or 644171589 counting only the distinct ones).

The product of its (nonzero) digits is 5715360, while the sum is 56.

The spelling of 1945397721620 in words is "one trillion, nine hundred forty-five billion, three hundred ninety-seven million, seven hundred twenty-one thousand, six hundred twenty".