1221337920 has 112 divisors (see below), whose sum is σ = 4230307008. Its totient is φ = 296079360.

The previous prime is 1221337891. The next prime is 1221337939. The reversal of 1221337920 is 297331221.

It is a Harshad number since it is a multiple of its sum of digits (30).

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, 47269 + ... + 68388.

Almost surely, 2^1221337920 is an apocalyptic number.

1221337920 is a gapful number since it is divisible by the number (10) formed by its first and last digit.

It is an amenable number.

1221337920 is an abundant number, since it is smaller than the sum of its proper divisors (3008969088).

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

1221337920 is a wasteful number, since it uses less digits than its factorization.

1221337920 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 115688 (or 115678 counting only the distinct ones).

The product of its (nonzero) digits is 4536, while the sum is 30.

The square root of 1221337920 is about 34947.6454142479. The cubic root of 1221337920 is about 1068.9201905366.

The spelling of 1221337920 in words is "one billion, two hundred twenty-one million, three hundred thirty-seven thousand, nine hundred twenty".