15780400 has 30 divisors (see below), whose sum is σ = 37913372. Its totient is φ = 6312000.

The previous prime is 15780383. The next prime is 15780407. The reversal of 15780400 is 408751.

It is a Harshad number since it is a multiple of its sum of digits (25).

It is not an unprimeable number, because it can be changed into a prime (15780407) by changing a digit.

It is a polite number, since it can be written in 5 ways as a sum of consecutive naturals, for example, 19326 + ... + 20125.

Almost surely, 2^15780400 is an apocalyptic number.

15780400 is a gapful number since it is divisible by the number (10) formed by its first and last digit.

It is an amenable number.

15780400 is an abundant number, since it is smaller than the sum of its proper divisors (22132972).

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

15780400 is a wasteful number, since it uses less digits than its factorization.

15780400 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 39469 (or 39458 counting only the distinct ones).

The product of its (nonzero) digits is 1120, while the sum is 25.

The square root of 15780400 is about 3972.4551602252. The cubic root of 15780400 is about 250.8260674439.

It can be divided in two parts, 157 and 80400, that multiplied together give a triangular number (12622800 = T₅₀₂₄).

The spelling of 15780400 in words is "fifteen million, seven hundred eighty thousand, four hundred".