19977940 has 12 divisors (see below), whose sum is σ = 41953716. Its totient is φ = 7991168.

The previous prime is 19977917. The next prime is 19977943. The reversal of 19977940 is 4977991.

It can be written as a sum of positive squares in 2 ways, for example, as 2304324 + 17673616 = 1518^2 + 4204^2 .

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (19977943) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 499429 + ... + 499468.

It is an arithmetic number, because the mean of its divisors is an integer number (3496143).

Almost surely, 2^19977940 is an apocalyptic number.

19977940 is a gapful number since it is divisible by the number (10) formed by its first and last digit.

It is an amenable number.

19977940 is an abundant number, since it is smaller than the sum of its proper divisors (21975776).

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

19977940 is a wasteful number, since it uses less digits than its factorization.

19977940 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 998906 (or 998904 counting only the distinct ones).

The product of its (nonzero) digits is 142884, while the sum is 46.

The square root of 19977940 is about 4469.6688915400. The cubic root of 19977940 is about 271.3419248561.

The spelling of 19977940 in words is "nineteen million, nine hundred seventy-seven thousand, nine hundred forty".