1521249978 has 32 divisors (see below), whose sum is σ = 3120122880. Its totient is φ = 494173440.

The previous prime is 1521249973. The next prime is 1521249997. The reversal of 1521249978 is 8799421251.

It is a happy number.

It is not an unprimeable number, because it can be changed into a prime (1521249971) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 264558 + ... + 270246.

It is an arithmetic number, because the mean of its divisors is an integer number (97503840).

Almost surely, 2^1521249978 is an apocalyptic number.

1521249978 is an abundant number, since it is smaller than the sum of its proper divisors (1598872902).

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

1521249978 is a wasteful number, since it uses less digits than its factorization.

1521249978 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 6822.

The product of its digits is 362880, while the sum is 48.

The square root of 1521249978 is about 39003.2047144847. The cubic root of 1521249978 is about 1150.0945046469.

The spelling of 1521249978 in words is "one billion, five hundred twenty-one million, two hundred forty-nine thousand, nine hundred seventy-eight".